LS-2136-E4 Instruction Manual 1 INSTRUCTION MANUAL FOR Nd:YAG LASER SYSTEM LS-2136-E4 CAUTION LASER DEVICES CONTAIN DANGEROUS HIGH VOLTAGES AND HIGH POWER ELECTROMAGNETIC RADIATION. INSTRUCTION SHOULD BE FOLLOWED CAREFULLY IN THE OPERATION OF THIS DEVICE. USE OF CONTROLS OR ADJUSTMENTS OR PERFORMANCE OF PROCEDURES OTHER THAN THOSE SPECIFIED HEREIN MAY RESULT IN HAZARDOUS RADIATION EXPOSURE Minsk 220012, Surganova Str., 6, Republic of Belarus Telephone 375 17 268 40 96, fax 375 17 284 06 21
Transcript
LS-2136-E4 Instruction Manual 1
INSTRUCTION MANUAL FOR
Nd:YAG LASER SYSTEM LS-2136-E4
CAUTION
LASER DEVICES CONTAIN DANGEROUS HIGH VOLTAGES AND HIGH POWER ELECTROMAGNETIC RADIATION. INSTRUCTION SHOULD BE FOLLOWED CAREFULLY IN THE OPERATION OF THIS DEVICE.
USE OF CONTROLS OR ADJUSTMENTS OR PERFORMANCE OF PROCEDURES OTHER THAN THOSE SPECIFIED HEREIN MAY RESULT IN HAZARDOUS RADIATION EXPOSURE
Minsk 220012, Surganova Str., 6, Republic of Belarus
Telephone 375 17 268 40 96, fax 375 17 284 06 21
LS-2136-E4 Instruction Manual 2
DANGER - LASER LIGHT The output radiation from the laser described in this Manual is capable of producing permanent eye damage, including blindness, of burning skin tissues or causing spontaneous ignition of chemicals or ordnance.
SAFETY REGULATIONS It is important that the user become familiar with the national safety and health regulations before operating a laser.
OPTICAL SAFETY CONSIDERATIONS Observe the following safety precautions:
* Do not stare directly into laser beam. * Disable high-power laser when performing boresight alignment precheck procedure with low-power laser. * When in laser operating area, wear protective goggles, which filter out the radiated wavelength. * Never view the laser beam through optical instruments. * Do not expose unprotected personnel or observers with binoculars. * Be sure the operating area is free of specularly reflective objects. * When testing, do not fire the laser into device with a reflective aperture. Avoid operation with direct reflection into laser system.
ELECTRICAL SAFETY CONSIDERATION
High voltage capable of causing death is used in this equipment. Use extreme caution when servicing the equipment during or after the equipment has been operated.
Never work on electronic equipment unless there is another person nearby who is familiar with the operation and hazards of the equipment and who is competent in administering first aid.
Always turn off the power supply before beginning work on the equipment. Ground every unit that might hold a dangerous potential. To work inside the equipment (with power off), always ground every part before touching it. Be careful not to contact electrical connections when installing or operating this equipment.
During operation, keep one hand away from equipment to reduce the hazard of current flowing through vital organs of the body.
LS-2136-E4 Instruction Manual 3
TABLE OF CONTENTS Section Title Page 1 Introduction..................................................................................................................... 4
2 Purpose and Operation Conditions ................................................................................. 5
15 Test Sheet........................................................................................................................ 25
16 Application …………………………………………………………………………….26
LS-2136-E4 Instruction Manual 4
MODEL LS-2136-E4 PULSED Nd:YAG LASER
1. INTRODUCTION
1.1. The purpose of this manual is to provide information to enable personnel to install, operate, perform routine
maintenance and test the basic performance of a pulsed Nd:YAG laser system supplied by “LOTIS”.
This manual describes the LS-2136-E4 Nd:YAG laser system. It is essential that all personnel concerned with lasers and their applications be familiar with the hazard warning given in this manual. Although the laser system which you purchased has been designed for operation with minimum of instruction, it is important that those who will be operating this Nd:YAG laser read the manual to gain an understanding of operation of the laser and the potential dangers associated with the misuse of the equipment. Please read this manual in its entirety before attempting to operate the laser.
1.2. Laser systems require high voltages for operation and emit electromagnetic radiation, which can be harmful. Please exercise caution when using this device. It is important that the user become also familiar with national “Medical rules for laser operation”
1.3. The manual has the following abbreviations PS power supply
CS cooling system
AE active element
SH second harmonic
FF fundamental frequency
wavelength of generated radiation
WS wavelength separator
LE laser emitter
FR free running
RC remote control
LS-2136-E4 Instruction Manual 5
2. PURPOSE AND OPERATION CONDITIONS
2.1. LS-2136-E4 is a pulsed Q-switched Nd:YAG laser lasing at the FF (1064nm) and the SH (532nm). It is
designed specially for use in four channels Engraving Laser System ELS-03 by “Lotis TII” production.
2.2. Operation conditions: According to National Standard laser system is operating in normal climatic conditions:
environment temperature (293 10)K, atmospheric pressure (84-108) kPa relative air humidity at 298K (40-80)%
2.3. The laser refers to class 4 hazardous radiation lasers according IEC 825-1 standard.
2.4. An internally sealed water cycle cooling system with water-to-air heat exchanger is utilised in the laser. The cooling capacity of the exchanger is 1000 W at environment temperature 20 C.
2.5. The laser is supplied by single-phase AC mains - (220 20) V, (50-60) Hz.
Fig.1. LS-2136-E4 external appearance
LASER POWER SUPPLY
LOCKING
Q-SWITCH LAMP
POWER SUPPLYLASER HEADCOOLING SYSTEM
CPU
POWER
EXT.TRIG SYNC.OUT EXT.TRIG SYNC.OUT
STOP
LASER COOLING SYSTEM
DRAIN
OVERHEAT
LEVEL
POWER
FLOW
LS-2136-E4 Instruction Manual 6
3. SPECIFICATION
3.1. The LS-2136-E4 is shown in Fig.1. Laser consists of the following parts: power supply PS-2241T laser emitter LE-2222ELS cooling system CP-1132 remote control RC-5
3.2. Specifications for “LOTIS” LS-2136-E4 Nd:YAG laser are provided in Table 1.
Table 1 Parameter Guaranteed value Note
Wavelength, nm 1064, 532 1064-FF, 532-SH Pulse Energy FF (E), mJ up to 70 Pulse Energy SH, mJ up to 30 Pulse Repetition Rate (f), Hz 1; 2; 5; 10; 25; 50; 100 Pulse Duration (FWHM), ns 12 Beam Divergency, (FWHM),mrad 1 Beam Diameter, mm 5 Polarisation of the SH radiation linear horizontal Pump Energy (Ep), J 10 Average pump power should be
less than 1000W, so as the frequency f is calculated from the equation Ep * f < 1000W
Power Consumption, W 1600 Input Power Requirements (220 20) V, (50-60) Hz
single phase, 10A
Dimensions, mm LE PS CS RC
850 220 140 446 449 177 446 449 266
115 175
Weight, kg LE PS CS
RC
21 18 24
0.5
without water in the internal loop
LS-2136-E4 Instruction Manual 7
4. DESIGN AND OPERATION
4.1. The laser operation is based on the stimulated photon emission from upper laser level of Nd3+ in YAG crystal excited by a pulsed pump (flash) lamp. A Pockels cell, made of DKDP crystal and polarizer derive electro-optical /4 Q-switch, which provides Q-switched output. The SH generation is obtained with the nonlinear KTP crystal cut for the type II phase matching.
4.2. Heraeus Noblelight lamp (5 75XFP) illuminates the Nd:YAG laser rod and produces the necessary
inversion of the energy level population of Nd3+. The lamp and AE are set in diffuse reflector, which provides the homogeneous illumination of AE and the filtration of UV part of pumping light.
4.3. Laser Emitter 4.3.1. Laser Emitter (LE) is one of the key parts of the laser, which provides the conversion of electrical
pump energy into laser radiation. In the LS-2136-E4 the triggering circuit and control plate of Q-switch are set in LE (See Fig.2). This arrangement of LE permits to eliminate high voltage connectors between LE and PS and so to increase laser safety and simplify laser construction.
4.3.2. The optical diagram of laser resonator is shown in Fig.3. The folded laser cavity is made of thrihedral corner cube prism (2), rear (5) and output mirrors (8). Q-switched mode is provided by the Pockels cell (3) and thin film polarizer (22). Rotator (23) is used for rotating polarization plane after passing the laser radiation across the prism (2). The intracavity mode-controlling telescope (4) fulfills two functions. One is to compensate for thermal lensing of AE, which is approximately a linear function of average input power to the flashlamp. With no optical adjustment whatever, the oscillator can run across a wide, continuous range of repetition rates and maintain low divergency. With simple adjustments to the telescope to compensate for thermal lensing in the oscillator, a full range of repetition rate from zero to the maximum system throughput can be realised. The second function is to limit the irreducible beam divergence of the system by decreasing the transverse mode content of the beam. By employing optics, which reduce the diameter of the intracavity beam between the telescope and the rear mirror, the diffraction length in the rear leg of the resonator appears longer than it really is and so the fundamental or TEM00 mode of the intracavity beam is larger than it would be in a convential stable resonator of similar length. A large TEM00 mode restricts the total number of higher order modes that are able to fit into limiting aperture and oscillate, there by reducing the beam divergence. Due to the known properties of thrihedral corner cube prism the folded cavity and hard mounted optics of the resonator is immune to thermal and physical shocks. LS-2136-E4 model has SH attenuator which consist of the polarizer 13 and /2 (532nm) retarding plate (12) - Fig.3. This attenuator serves for change of output SH energy by rotation /2 plate rotation about it axis without variation of pump energy. The procedure of changing output SH energy consists in rotation of calibrated microscrew on the lateral side of LH. Please use calibration curve (see Application in this Manual) for precise attenuator adjustment. Output telescope (17) is used for beam diameter expanding and compensation of beam divergency. System of beam-dividing mirrors (18-20) is used for dividing of laser beam on four beams with identical energy values. Channel shutters are used for selection of needed channels to operate.
4.4.1. PS is designed for supplying flash lamp, control of Q-switch and energy indication of FF and SH. 4.4.2. Specifications of PS-2243 are provided in Table 2. 4.4.3. The controls and indicators for the model PS-2241T are listed and described in Table 3 and shown
in Fig.4. 4.4.4. A special connector (socket) (26) is provided for user to fit an external emission lamp if it required.
Pins 3 and 4 carry 220V 0,5 A supply for such lamp. 4.4.5. A socket (27) is provided for the user to connect an external interlock if wanted, or required by
local safety regulations. An example is the interlocking of the door of the room where the laser is kept so that if some one was to open the door when laser was operating the laser would be turned off, ensuring that the person was not risk from the laser radiation. The interlock is “safe” when interlock switch is closed. Pins 1 and 2 are the active pins on the interlock connector carrying a supply voltage of 12V 1 mA. This system is supplied with a plug in which pins 1 and 2 are connected.
Table 2
Parameter Value
Input power requirement (220 20)V, (50-60)Hz single phase 5A Average pump power, W 2000
Max.pump energy, J 15 Pump pulse duration, s 80-100
Parameters of output synchropulse *: Lamp output Duration, s 15 – 25
(time between lamp triggering and Q-switch triggering, for EXT 1 mode only)
time gate, s 0-70
(time between lamp triggering and Q-switch permission signal, for EXT 2 mode only)
amplitude, V 3 – 5 polarity Positive *There are two connectors of output synchropulse in PS-2241T. The first one is correlated to pump pulse and the second to Q-switch synchropulse. The more precise synchronisation with laser pulse is provided by the synchropulse from Q-switch output
LS-2136-E4 Instruction Manual 10
1
4
3
2
5 6 7 8
A) Front Panel
B) Rear panel
C) Remote Control
Fig.4 Power supply PS-2243 with remote control
12
11 9
10
28
13 14
26
27
15
16
23
17
18
19
24
20
21
25
22
LS-2136-E4 Instruction Manual 11
Table 3 Position on Fig.4 Designation Function
1 Power ON/OFF Key for switching ON/OFF laser system 2 Stop Emergency Button for immediate switch off laser system
3 Locking PS, LH, CP, CPU
Red indicators of laser interlocks
4 Power Indicator of input power 5 Q-Switch ext. trig. input of external triggering of Q-SW
6 Q-Switch sync. out Output of synchropulse correlated to the Q-SW triggering pulse 7 Lamp ext. trig. input of external triggering of pump lamp
8 Lamp sync. out Output of internal synchropulse correlated to pump pulse 9 Control LH Connector for cable of LE control
10 Remote control Connector for cable of RC-5
11 PC 200 240 V 50-60 Hz
Power cord line with outlet fuses
12 Laser Connector for LE 13 CP Connector for CS interlocks and power supply 14 Ground electrode 15 Digital screen of laser operation regimes 16 Function Button for switch parameter indicated on screen 15 17 Buttons changing values indicated on screen 15 18 Display Button for selection parameter indicated on screen 15
19 Lamp Button and indicator for switching on power circuit and pump lamp operation
20 Shutter Button and indicator for shutter control 21 Q-Switch Button and indicator for switching on Q-Switch function 22 Status Indicators of “stand by” regime and triggering of power circuit 23 Stop Button for switch off laser system 24 Lamp mode Button and indicators for pump lamp operation control 25 Q-SW mode Button and indicators for Q-switch operation control 26 Ext. lamp External emission lamp connector (socket) 27 Ext. interlocking External interlock socket 28 Ext. control External control socket
4.5. Cooling system CP-1132
4.5.1. The internally sealed CS is designed for cooling the flash lamp and AE. CP-1132 consists of centrifugal TOTTON pump GP 20/18, tank, water-to-air heat exchanger, deioniser; fan, flow, level, temperature sensors and control plate.
4.5.2. CS has the following parameters: max heat exchange, W 1800 power requirements, W < 200 (220 20)V, (50-60)Hz volume of liquid , l < 2 capacity, l/min up to 6
4.5.3. The dissipated by the CS heat is strongly depend on the difference between the water temperature and the temperature of ambient air.
LS-2136-E4 Instruction Manual 12
ATTENTION
1. THE MAXIMUM TEMPERATURE OF COOLING WATER MUST BE NO MORE THAN 50 C, IF THE TEMPERATURE OF THE WATER IS HIGHER THAN 50 C THE INTERLOCK SYSTEM COMES INTO ACTION.
2. CS OPERATES EFFECTIVELY ONLY IF THE AMBIENT TEMPERATURE IS NO MORE THAN 303 K (30 C).
3. CS MUST BE INSTALLED SO THAT ITS POSITION WILL MAINTAIN FREE FLOW OF AIR ACROSS THE FAN OF CS.
4.5.4. The controls and indicators for the model CP-1132 are listed and described in Table 4 and shown in
Fig.5.
Table 4__
position in Fig.5 designation function
1 power on/off power switch
2 overheating red indicator of overheating water in the internal loop (T>50 C)
3 level indicator of water level 4 power green indicator of power supply 5 flow green indicator of normal water flow 6 PS connector of interlock PS and power 7 ground electrode 8 laser in/out laser input/output water coupling 9 2A fuse
10 drain point for discharge water in CS 11 Fan of heat exchanger
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5. LIST OF DELIVERED EQUIPMENT Names of article, designation and quantity of complete set units are given in Table 5
Table 5
Name of article Designation Quantity Note
LE LE-2222ELS 1 Power supply PS-2243 1 CS with deioniser CP-1132 1 Cable N1 1 Cable N2 1 Hose 2 Set of spare parts:
visualizer 1
for definition the shape of FF radiation spot
adjustment key 1 for laser head adjustment fuse 2.0A 1 funnel 1 rubber o-ring 4 fuse 10A 2 spanner 12 14 1 for removing flash lamp electric socket 1
Power cord line 1 Mounting Screws 3 Discharge water hose 1
6. SAFETY PRECAUTIONS
6.1. There are special hazards associated with laser equipment the user must be familiar with to ensure his or her safety. The green and invisible infrared pulses of coherent light emitted from the laser described in this manual are capable of inflicting permanent eye damage and could result in total blindness. The light output from this laser can burn skin tissue and may cause spontaneous ignition of chemicals on some common materials. If at all possible, laser work should be performed in a light tight enclosure with safety interlocks.
6.2. Optical safety considerations, safety regulations and electric safety considerations presented on summary safety pages at the front of this manual should be reviewed and safety rules applicable to “Medium Power” and “High Power” laser should be carefully observed, as prescribed below enclose the entire laser beam path if at all possible confine indoor laser operations to light laser cannot emit when door is open ensure that all personnel wear adequate eye protection.
6.3. Use remove firing and video monitoring or remote viewing through a laser shield if feasible Assume that laser device has a key switch master interlock to permit only authorised personnel to
operate the laser. Install appropriate signs and labels at site of laser operations. Use beam shutters and laser output filters or beam traverse and elevation stops to restrict beam interception
on outdoors laser devices Use dark, absorbing, diffuse fire-resistant targets and backstops where feasible Use a continuing laser safety educational program for people operating the system or otherwise in vicinity
of the laser. 6.4. All blocks having ground electrodes should be grounded 6.5. It is forbidden:
LS-2136-E4 Instruction Manual 14
to operate without grounding to introduce any changes into electric line or power supply to operate with protective cover of LE removed to operate with the presence of scattered laser light, reflected from optic elements, beam splitters, entrance
windows of beam analyser etc. to expose optics elements (lenses, prisms, etc) to beam of the laser, operating in nominal mode to operate in the modes with the laser parameters exceeding those specified in manual. The energy of FF
should be no more than 100 mJ. to operate without protective cover of Q-switch . to detach water hoses if the water temperature is more than 30 C.
7. INSTALLATION
CAUTION It is desired that all installation of LS-2136-E4 Nd:YAG laser be performed after consultation with service representative of “LOTIS”.
7.1. Unpacking procedures
All packaged equipment should be handled as directed by handling procedures. Unpacking and set up should be performed according to the following instructions:
make sure that the box with laser is in right position in accordance with exterior box marking.
CAUTION Use care to avoid damaging equipment while removing box avoids stressing cable.
7.2. Check packing list against material received. Report any deficiencies to “LOTIS” immediately. 7.3. Visually inspect equipment for damage. Note and report deficiencies to responsible authority. 7.4. THE LASER SHOULD BE USED IN A DRY, LIGHT ROOM WITH INCOMING-EXHAUST
VENTILATION AS TO MEET REQUIREMENTS: AMBIENT TEMPERATURE (283-303)K RELATIVE HUMIDITY (40-80)% ATMOSPHERE PRESSURE (84-104)kPa 7.5. Electric requirements:
(220 20) V, (50-60) Hz, single phase, 10A, grounding system
7.6. Cooling water requirements:
use only double distilled water. Do not user commercial grades of distilled water.
7.7. Setup procedure
7.7.1. The base plate of LE has 3 supports, which allow to fix LE. Three mounting screws are used for the connection of LE to the optical table. Place laser emitter on a suitable work surface with beam exit port facing target area and fix LE with mounting clamps.
7.7.2. Verify that all power switches are OFF. We strongly recommend set up CS below the LE. Such installation is convenient for change pump lamp and water in the CS. CS must also be installed so that its position will maintain free flow of air across the heat exchanger.
LS-2136-E4 Instruction Manual 15
POWER200-240 V
LaserControl LH
CP
Power Supply PS-2241T
water in
water out
Emitter LE-2222ELS
PS
IN
OUTLaser
Cooling System CP-1132
RC-5Remote control
Fig.6. Electro-hydraulic function schematic. 7.7.3. Couple the LE, PS, RC-5 and CS according to the electro-hydraulics junction schematic shown in Fig. 6.
The umbilical cable connects the LE to the power supply (connector “Laser”) and contains electrical cables providing the required power and signals for the LE. PAY A SERIOUS CONSIDERATION TO PROVIDING GOOD CONNECTION BETWEEN CONNECTOR 12 “LASER” ON REAR PANEL OF PS AND UMBILICAL CABLE. YOU ALSO SHOULD CONCENTRATE ATTENTION ON THE CONTACTS BETWEEN WATER HOSES AND APPROPRIATE COUPLINGS. LEAKS ARE USUALLY OBSERVED AT PIPE CONNECTIONS.
7.7.4. Verify secured states of all equipment subassembly covers. When the LE protective cover is removed, or
when cables are disconnected, a safety interlock circuit will prevent operation. 7.7.5. Verify that the power ON/OFF switch is in the OFF position. 7.7.6. Plug the power cord line into a 200-240V, 50-60 Hz single-phase outlet on a circuit of 10A or greater
capacity. The indicators “stand by” at the RC-5 and “power” at the PS and the Q-switch heating begin to emit red radiation.
NOTE. 1. THE HEATING OF Q-SWITCH SHOULD BE CARRIED OUT AT ALL TIMES AFTER
INSTALLATION OF LASER. 2. OTHER SWITCHING SHOULD BE OFF AS A MATTER OF GOOD PRACTICE UNTIL
OPERATIONAL STEPS REQUIRE ENERGISING A UNIT.
WARNING OBSERVE ALL SAFETY PRECAUTIONS FROM SEC. 6, WARNING PAGES AND OPERATING INSTRUCTION. MAKE SURE ALL PERSONNEL ARE WEARING EYE PROTECTION GOGGLES SUITABLE FOR WAVELENGTH OUTPUT OF THE EMITTER.
7.7.7. Set up the switch "Power" (1) on the rear panel of CS in the “ON” position, the indicator “Power” (4) of CS
begin to illuminate, the indicator “Level” begin to blind with red light.
LS-2136-E4 Instruction Manual 16
7.7.8. Undo 2 screws M4 on the rear side of CS, detach ground wire under the cover and remote the upper cover from CS. Unscrew the plug of the water tank and using the funnel from set of spare parts fill the tank by the double distilled water till the indicator “Level” will begin to emit continuously green radiation. Do not use commercial grades of distilled water. Screw the plug of the tank, connect ground wire and set up the upper cover of CS.
8. OPERATION
The model LS-2136-E4 pulsed Nd:YAG laser is operated by the controls on the RC-5 panel. The controls have been reduced to the essential number for ease of operation by all but the most inexperienced operator. Nevertheless, it is important to read the following section before operating the laser to reduce the likelihood of faulty operation.
WARNING EYE DAMAGE MIGHT RESULT FROM THE LASER OUTPUT. BOTH DIRECT AND REFLECTED BEAMS ARE DANGEROUS. WEAR EYE PROTECTION FOR THE OUTPUT WAVELENGTH OF THE LASER. ENSURE THAT LASER BEAMS DO NOT IMPINGE ON ANYONE.
8.1. Pre-operation procedure. 8.1.1. Open the shutters (21) from the outputs 532nm of the LE. 8.1.2. Insert the key into the lock “Power” at the front panel of PS. 8.1.3. Set up “Power” key switch in the “ON” position. The CS is switched and “Power”, “Flow” and
“Level” green indicators on the front panel of CS are illuminated. The indicator "Power" at PS (4), "Lamp mode" (24) and "Q-SW mode" (25) at RC-5 emit green radiation, lamp indicator (19) emits “red” light. Digital green indicator (15) is illuminated too. Indicator “stand by” (22) is gone out. Check up that there is no water leakage and indicator “Level” (3) at the CS continuously emits. If there is deficit water in CS the laser send tone and the “Level” indicator begin to flash. Add deionised water in CS according s. 7.7.8 until the “Level” indicator will continuously radiate green light.
8.1.4. The laser parameters control is executed by the buttons "Function" (16), (17) and "Display" (18).
The increasing of pump energy is performed by press right button (17) and decreasing - by the corresponding left button (17). Step of energy change is 0.1 J. The buttons "Function" (16) and "Display" (18) provide the switch pump parameters, which can be indicated on the screen (15). For switching press simultaneously the buttons (16) and (18). The appropriate parameter is indicated at the screen. The following press of button (18) will change again indicated parameter to next. The switch is performed circularly: pump energy pulse repetition rate delay of Q-Switch triggering duration of simmer (without laser pulses) output energy of FF output energy of SH pump energy etc. Change the value of the selected parameter is conducted by the buttons (17) as above written for pump energy change.
LS-2136-E4 Instruction Manual 17
ATTENTION Pump lamp of laser continuously operates with pulse repetition rate 50 Hz. Change of laser frequency is made by
changing the frequency of Q-Switch opening. This operation mode conserves the thermo-optic parameters of the laser rod at different repetition of output pulses.
8.1.5. Pump lamp mode selection is executed circularly by pressing the button (24):
Internal – internal triggering of pump lamp according pulse repetition rate at the screen (15); External - triggering of pump lamp by external pulse at the connector “lamp ext. trig.”; "Lamp Mode", "1 HZ" and "single shot" don't use in LS-2136.
8.1.6. Q-Switch mode selection is executed circularly by pressing the button (25) and is defined by corresponding green indicator (25): Internal – internal triggering with the delay, set at the screen (15) and lamp pulse repetition rate; ext. 1 – triggering with external pulse delay at the connector Q-Switch ext. trig.; ext. 2 – triggering with internal delay and external pulse repetition rate; single shot – armed triggering of Q-Switch by pressing button (21).
8.2. Turn on procedure. 8.2.1. Set up energy value 9 J. Check that delay corresponds the value in the Test sheet.
NOTE. AT FIRST LASER SWITCH WE STRONGLY RECOMMEND TO BEGIN OPERATION IN FR MODE.
8.2.2. Press the button "Lamp" (19) at RC. During the switching procedure short sound melody plays out. After no more 10 s the indicator “High Voltage” is illuminated. Power circuit of PS is come into action. Indicator “Lamp” begins to flash at first with red colour. After beginning of simmer indicator’s colour is changed to green. When this indicator permanent emits green lights laser is ready for emitting radiation.
ATTENTION
The green indicator “Lamp” continues to flash until the temperature of the water in CS is lower than 35 C and heat steady state of laser is not reached. During this period ( 5-10 min) Q-Switch is closed. Shutter is in the resonator. Only when the flashes are ended and the indicator “Lamp” is illuminated continuously it is possible to open Q-Switch, remove shutter from optical axis of resonator (by pressing the button “Shutter” see s.8.2.3.).
8.2.3. Press the button “Shutter”, the corresponding red indicator is switched and the green spot of SH radiation is appeared on the white screen set up in front off LE output. For interruption laser radiation press the button “Lamp” or press the button “Shutter”. At first case pump lamp ends discharge and operates only in simmered mode, in the second – lamp continues to flash and shutter is introduced in laser resonator.
8.2.4. To change laser operation mode from FR to Q-Switch set the switch (24) at the RC-5 panel from “FR” into the "internal" (or other) position. Press the button Q-Switch (21) at the panel of RC. The corresponding green indicator (21) is illuminated and Q-Switch operates in one of the following mode: internal, ext.1, ext.2, single shot. This mode is indicated by the light of the corresponding indicator and is changed by pressing the button (25) (see s.8.1.6). After repeat pressing the button (21) Q-Switch becomes closed and the corresponding indicator (21) is gone out. When Q-Switch is closed, laser does not generate.
8.2.5. Set up the head of energy (power) meter in front of LE, press the button "Lamp" (shutter is opened)
and measure the energy of laser generation in Q-Switch mode. 8.2.6. The laser parameters’ stabilisation occurs after 5-10 min. Continuous operation of the laser should
not exceed 8 hours. 8.2.7. As a check on the laser energy of FF (1064 nm) in operation press the button display (18) and
display (15) will indicate the level of laser radiation. IT SHOULD BE NOTED, THAT THE INDICATOR DOES NOT GIVE THE EXACT VALUE OF THE ENERGY, BUT SERVES TO CONTROL THE OUTPUT ENERGY OF LASER WITHOUT EXTERNAL ENERGY (POWER) METER. Furthermore, this indicator alloys to determine the FF energy without removing KTP crystal and wavelength separators.
8.2.8. For external triggering press the button (24) "Lamp mode"; the green indicator "ext" is illuminated. Connect the output of the source of synchropulses to the connector (7) (Fig.4). Turn on laser according s.8.1.4 - 8.2.4. The parameters of synchropulse should comply with ones of the Table 2. Turn on the source of synchropulses. Press the button “Lamp”. Laser begins performance.
LS-2136-E4 Instruction Manual 18
8.2.9. For external triggering of Q-switch connect the output of the source of external triggering pulse to the connector (5) (Fig.4). We recommend to switch the source of external triggering pulse by the output of lamp synchropulses (connector 8. Fig.4). Turn on laser according s. 8.1.4 - 8.2.4. Press the button "Q-SW mode" (25), the green indicator "ext1" is illuminated. In this case the parameters of synchropulse should comply with ones of Table 2.
The delay between pulse of output 1 and synchropulse should be equal to the value in Test sheet. After the repeat pressure of the button "Q-SW mode" (25) the green indicator "ext2" is illuminated. In this mode Q-Switch operates with internal delay (see s.8.1.6). Turn on the source of synchropulse. Press the button “Lamp” (19).
ATTENTION
1) DURING “TURN ON” PROCEDURE AND OPERATION CAREFULLY CARRY OUT ALL SAFETY PRECAUTIONS FROM PART 6.
2) IF THE ENERGY OF FF EXCEEDS 100 mJ TO AVOID DAMAGE OF THE OPTICAL ELEMENTS THE INTERLOCK SYSTEM COMES INTO ACTION AND LASER TURNS OFF.
8.2.10. LS-2136-E4 can work in free running mode (without Q-switch action). This regime is convenient
for adjustment and alignment procedures. For operation in FR. mode turn on the switch in LE in the position “FR” or set “FR” regime on RC-5 panel (Fig.2).
8.2.11. Variation of output SH energy at constant pump lamp energy is evaluated by rotation of the corresponding microscrew of /2 plate holder (according tuning curve in Application) marked “A” on the lateral side of LH.
8.3. Turn OFF procedure
8.3.1. “Turn off” procedure is fulfilled when laser does not generate that is after pressing the button “Lamp”.
8.3.2. Press the push button “Stop” (23) at the panel of RC. Wait 5 s and turn the key (1) to the position Power “OFF”.
ATTENTION
1) IF SYSTEM DOES NOT ENERGISE CHECK ALL SYSTEM INTERLOCKS AND VERIFY THAT THE INTERLOCK CIRCUIT IS CLOSED BEFORE PROCEEDING.
2) IF THE COOLING WATER TEMPERATURE REACHES 50 C. THE INTERLOCK SYSTEM
COMES INTO ACTION AND THE INDICATORS “OVERHEATING “ IS ILLUMINATED. WHEN THIS INDICATOR IS GO OUT YOU MAY CONTINUE OPERATION.
3) BUTTON “LAMP” FULFILLS TWO FUNCTIONS START AND STOP. AT FIRST PRESSING
OF THIS BUTTON LASER BEGINS TO GENERATE OUTPUT PULSES, AFTER THE REPEAT PRESSING OF LAMP BUTTON LASER STOP GENERATION AND LAMP WORKS ONLY IN SIMMERED REGIME.
4) THE MODE “FR” IS USED ONLY AT ADJUSTMENT AND ALIGNMENT. IF THE SWITCH
“FR-QSW” IN LE IS IN THE POSITION “Q-SW” - LASER OPERATES IN Q-SWITCHED REGIME, AND WHEN SWITCH IS IN THE POSITION “FR” - LASER OPERATES IN FREE RUNNING MODE. ANY SWITCHING THE SWITCH “Q-SW” TO “FR” AND REVERSAL SHOULD BE MAKE ONLY AFTER GENERATION STOP BY PRESS THE BOTTOM “LAMP”.
5) AFTER TURN OFF BY PRESSING THE BUTTON “STOP” (23) AT RC LASER WILL CONSERVE FOR THE NEXT SWITCHING SUCH PARAMETERS AS PULSE REPETITION RATE, INTERNAL DELAY OF Q-SWITCH, SIMMER DURATION AS WELL AS LAMP AND Q-SWITCH MODES. TO AVOID SPONTANEOUS CHANGE THE VALUES OF ABOVE MENTIONED PARAMETERS LASER TURN OFF BY THE POWER KEY IS CLEARED ONLY AFTER MORE THAN 5 S AFTER PRESS THE BUTTON “STOP”
6) THE BUTTON “STOP” AT THE PANEL PS IS USED FOR IMMEDIATE TURN OFF LASER
ONLY IN EMERGENSY. FOR NEXT INITIATIONS OF LASER OPERATION IT IS
LS-2136-E4 Instruction Manual 19
NESSESARY AT FIRST TURN KEY (1) TO THE OFF POSITION, WAIT MORE THAN 5 S AND THEN REPEAT TURN ON PROCEDURE ACCORDING S.8.1. - 8.2.
9. LASER ADJUSTMENT
ATTENTION THE USING IN LS-2136-E4 Nd:YAG LASER THE FOLDED CAVITY WITH CORNER CUBE PRISM MAKES THE RESONATOR NONSENSITIVE TO DEFORMATION OF LE AND THE ADJUSTMENT OF LASER MIRRORS IS NOT REQUIRED. FOR THIS REASON THE ADJUSTMENT OF LASER IS INCLUDED IN ALIGNMENT OF THE TILT OF KTP CRYSTAL TO ACHIEVE THE MAXIMUM ENERGY OF SH RADIATION
9.1. Laser alignment should be adjusted only if necessary. It is recommended that “LOTIS” be contacted prior to alignment adjustments. A trained, experienced laser technician should only perform any alignment beyond minor adjustments. We advice that you contact us if you ever experience any difficulties with LS-2136-E4 laser. Our service department is dedicated to providing prompt, continuous service to restore your laser to good working condition.
NOTE
SWITCHES SHOULD BE OFF AS A MATTER OF GOOD PRACTICE UNTIL OPERATIONAL STEPS REQUIRE ENERGISING A UNIT.
WARNING
EYE DAMAGE MIGHT RESULT FROM THE LASER OUTPUT. BOTH DIRECTED AND REFLECTED BEAMS ARE DANGEROUS. WEAR EYE PROTECTION SUITABLE FOR WAVELENGTH OF THE LASER. BE SURE LASER OUTPUT BEAM DOES NOT INTERCEPT PASSER-BY.
9.2. Adjustment Procedure 9.2.1. Set up the head of power (energy) meter in front of LE output (the distance between LE and head >
0,5 m).
9.2.2. Switch on laser according to section 8. The pump energy should be less than 7 J. Align the position of power (energy) meter head so that the radiation falls onto the centre of the head. We recommend for alignment laser operation in FR mode.
9.2.3. Set up the desired pump energy and frequency. Remove circular protective cover of the SH adjusting screw. Using screwdriver by rotating adjusting screw of the KTP holder get the maximum energy of SH radiation.
9.2.4. If after adjustment according to S.9.1 - 9.2.3. the energy is not nominal it is necessary to
remove the protective cover of LE unscrewing the screws at the upper side of LE. Remove /2 plate holder .
Extend the rod of the interlock button Fig.2. unscrew the screw of cover, which closes the mount of rotator and KTP crystal. remove KTP crystal and WS-mirror set up the visualizer from the set of spare parts in front of power meter head switch on laser in FR mode - the bright green spot appears on the visualizer. slightly rotating the adjusting screws of intracavity telescope holder maximise the brightness and
homogeneity of laser spot. For better adjustment it is possible to set up the neutral filter between the laser
LS-2136-E4 Instruction Manual 20
and visualizer. The transmission of each filter at FF ( =1064 nm) should be 50 %. We recommend to adjust the laser at the desired pump energy and pulse repetition rate; Check the spot form in Q-SW mode
remove the visualizer and check up that the energy of FF radiation satisfies the nominal value. if you desire to operate with SH radiation, set up the KTP crystal and wavelength separators and maximise
the energy of SH according to S.9.2.3. - 9.2.6.
NOTE 1. LASER IS DELIVERED ADJUSTED IN NORMAL CLIMATIC CONDITIONS (see S.2.2.) 2. THE POLARISATION OF THE SH RADIATION IS HORIZONTAL AND ANGLE BETWEEN THE
POLARISATION OF SH AND FF LIGHT IS 45 .
9.3. After adjustment set up all covers, holder of /2 plate, set up the cover of LE; laser is ready for lasing. Undo circular nut at the upper plate of LE protective cover. Using screw driver by rotating microscrew of /2 plate holder get the maximum energy of SH radiation.
10. IDENTIFICATION AND ISOLATION OF MALFUNCTIONS
10.1. A malfunction of laser will usually be apparent as either a total absence of laser output or an erratic or low output. Do not perform any repairs or alterations to the laser system while it is in warranty without permission of “LOTIS”. To do so will avoid warranty.
10.2. A list of possible faults is given in Table 6.
Table 6
Fault Cause Remedy
No discharge on pump lamp Lamp is defective
Replace defective lamp according to S.11
Pump pulse energy is lower than nominal or there is no lasing
1. Pump lamp efficiency has by (10-20)% dropped during operation time
2. LH is misaligned - fuse is blown
Increase pump energy Replace pump lamp according to
Sec.11 Adjust LH according to Sec. 9.
When Power switching on, indicators do not illuminate
fuse is blown
Replace fuse on rear panel of PS
When switch of CS is in position ON, indicator power does not illuminate
fuse is blown Replace fuse on the rear panel of CS
During lasing “overheating” indicator illuminates, because the interlock system comes into action
the temperature of the cooling water is >50 C
Check up that the fan of CS is free and draws external air through the CS
Turn on laser after 15 minutes when indicators “overheating” CS illumination is ended
LS-2136-E4 Instruction Manual 21
11. PREVENTION MAINTENANCE AND SERVICE
11.1. The service section is divided into preventive maintenance, identification and isolation of malfunctions. Opening the laser head for inspection is not recommended unless a specific malfunction is apparent. Adjusting laser alignment should only be resorted to in the event that all other possibilities for malfunction have been eliminated. It is recommended that “LOTIS” be contacted prior to any corrective maintenance so that proper procedure and precautions can be followed.
11.2. It is important to have general understanding of laser system functions before performing maintenance functions or service functions, read Sections 1 - 10 before proceeding.
11.3. To provide a reliable work of the LS-2136-E4 it is necessary to carry out the following operations:
replacement flashlamp if output energy decreases ~ 30% (at least 2 107 pulses) replacement of the water in the CS every month periodic cleaning of CS one time in 4 months.
11.4. Pump lamp replacement requires opening of the LE. Turn off the power switch and unplug the power supply. 11.4.1. Set up LE above CS. 11.4.2. Remove the protective cover from LE. Remove two protective tubes, which protect AE. 11.4.3. With the great caution remove the cable lugs from the electrodes of lamp, undo 3 screws fix pump
chamber, remove the chamber. Place a paper towel or other absorbent material under the laser chamber. 11.4.4. Using the spanner from the set of spare parts unscrew the retaining nuts of lamp on each end of
laser chamber. Remove the nuts and the pump lamp O-ring cells and withdraw the lamp through the laser chamber.
11.4.5. Install the new lamp, observing proper polarity. Install new O-rings if available.
11.4.6 Reseal the lamp with retainer plates carefully, remove all exterior traces of coolant. 11.4.7 Set up the laser chamber into the LE and fix with the appropriate screws. Install cable lugs on the
electrodes of lamp or attached the ends of lamp wires to the triggering unit. Set up protective tubes. 11.4.8 Turn on the CS, the pump will start. No water should be allowed to contaminate the LE. If no liquid
leakage is observed, replacement procedures can be resumed. Set up the cover of LE. 11.4.6 Turn on laser. Adjust LH if available according to Sec.9.
11.5. Change the water in the cooling system. 11.5.1. Set up LE above CS undo 2 screws on the rear side of CS and remove the upper cover of CS.
Remove the plug from the tank of CS, unscrew the nuts and unconnected water hoses from the pipes on the external side of rear panel of LE. Sink the couplings and discharge the water from the tank in the suitable vessel. It is convenient to discharge water by connection the hose from complete of spare part to valve “DRAIN” at the rear panel of CS (Fig.5).
11.5.2. Connect the water couplings. Using the funnel from the set of spare parts fill the tank with double distilled water till the water level indicator begin to light permanently (See s.7.7.8, 7.7.9).
11.5.3. Switch on CS. No water should be allowed to contaminate the LE. If no water leakage is observed, replacement procedures can be resumed.
11.6. Cleaning of the cooling system. 11.6.1. Cleaning of the CS is carried out every four months. 11.6.2. Discharge the water from the CS according s.11.5.1. Connect one of the hose to the pipes “IN” and
“OUT” on the rear panel of CS. Fill the tank of CS with mixture of 10% ethyl alcohol and 90% distilled water according to s.11.5.2 and switch on CS. After approximately 1 hours of operation switch off CS and discharge mixture.
11.6.3. Remove the upper cover of CS unscrew the appropriate screws. Remove the cover of tank unscrew the screws, using the clean cotton cloth cleaning the tank to remove deposition organic and mineral deposit. Clean the heat exchanger plates by vacuum cleaner. After that set up the covers of tank and CS. Connect hoses according S.11.5.2.,11.5.3.
11.7. Optical cleaning. The surface to be cleaned should be brightly illuminated with a high intensity light so that small dust particles or thin greasy films can be seen.
LS-2136-E4 Instruction Manual 22
CAUTION. DO NOT TOUCH OPTICS WITH BARE FINGERS. ALL OPTICAL ELEMENTS ARE PRECISION DIELECTRICALLY COATED COMPONENTS AND SHOULD BE HANDLED ONLY BY TRAINED PERSONNEL.
11.7.1. THOROUGHLY EXAMINE ALL OPTICAL SURFACES USING A HIGH INTENSITY LAMP AND A SMALL INSPECTION MIRROR TO LOCATE ANY BURNS OR DIRT THAT COULD BE RESPONSIBLE FOR DEGRADED PERFORMANCE .IF DUST OR DEPOSITED FILM IS PRESENT, LASER OUTPUT WILL BE REDUCED AND THE OPTICAL ELEMENTS COULD BE DAMAGED. DUST PARTICLES ON THE OPTICS ABSORB THE LASER ENERGY AND MAY CAUSE DAMAGE TO THE COATING AND THE GLASS SURFACES. BLOW DUST OR DIRT PARTICLES USING CLEAN DRY AIR.
11.7.2. IF CLEANING IS REQUIRED TO REMOVE A FILM USE A REAGENT GRADE OF DENATURED ETHULALCOHOL. APPLY THE SOLUTION WITH SLIGHTLY MOISTENED OPTICAL COTTON, SWAB AND DRY ANOTHER SWAB AS FOLLOWS.
12. MEASURING LASER PERFORMANCE. The unique qualities of laser radiation can create difficult measurement problems if improper measuring equipment is employed. Today there is a large number of products on the market designed specifically for making laser measurements. To obtain accurate measurements, it is suggested that equipment designed for your particular need be obtained and that correct testing procedures be followed.
12.1. Energy measurements 12.1.1. Types of measurement devices. Most laser energy measuring devices are based on photo-, pyro-
effects or thermocouples. In the case of either type of instrument the user must be careful not to exceed the manufactory recommendation for maximum energy or peak power, to assure accurate measurement and prevent damage to equipment.
12.1.2. Follow the laser set up procedure described in S.8. Aim the laser beam at the input aperture of the energy measuring device head by careful positioning before turning the laser “ON”.
WARNING
Eye damage might result from the laser output. Both direct and reflected beams are dangerous. Wear eye protection suitable for wavelength output of the LE. Ensure laser beam does not intercept passer-by.
12.1.3. Operate the laser and make sure the beam is accurately centred in the input aperture of energy meter
head with no vinetting. Developed, unexposed black and white photo paper (or film) makes an excellent material for checking the beam position. For FF radiation the most suitable device for observing light is visualizer. If you measure the average power of laser radiation it is easy to calculate the generation energy (Eg) from the equation:
Eg = P/f,
where f is the pulse repetition rate, P is the average power
12.2. Pulse width measurement The equipment that is needed to measure the pulse width includes a high-speed photodiode or a similar detector and an oscilloscope with a rise time of < 2 ns.
12.2.1. Connect the output of the detector to the oscilloscope. Scatter radiation from a diffuse surface. For FF an ordinary white paper is satisfactory.
12.2.2. Detect the radiation scattered from the diffuse surface with detector and observe the pulse on the oscilloscope. Read the half-power points on the oscilloscope to determine the pulse width 0.5 (FWHM)
12.3. Beam divergence measurement Definition - Beam divergence is defined as the full beam angle that contains 50% of the laser energy. 12.3.1. Measurement procedure:
LS-2136-E4 Instruction Manual 23
Set up the laser system as described in S.5.8. Equipment required is listed below:
a lens of focal length between 1 and 3 meters an aperture plate containing a number of round holes of various diameters. x-y translator or other means for translating the aperture plate an energy measuring device as described in S.12.1 a set of neutral filters (The neutral filters are set to avoid damage of aperture plate and detector).
12.3.2 Set up of equipment is as shown in Fig.7. Neutral filters attenuate the pulse to safety value. Operate the laser without the aperture plate in place to obtain a reference reading of 100% of the laser energy pulse.
12.3.3. Place the aperture plate at the focal plane of the lens and centre the beam on one of the holes. Measure the energy transmitted through the hole. Try different hole sizes until a diameter is found that transmits 86% of the laser energy.
12.3.4. Beam divergence calculation The beam divergence, measured in radians is diameter (D) of the aperture that transmits 86% of the laser energy divided by the focal length (F) of the lens:
0.86,rad= D/F
LS-2136-E4 Instruction Manual 24
13. TRANSPORTATION AND STORAGE
13.1. Laser can be shipped in the package of the manufacturer by railway in box- carriage (without any distance or velocity limitations) or by cars in trailers along cobble-stone or dirt roads at a velocity of 20-30 km/h, or along asphalt roads at the velocity of 40-80 km/h (without any distance limitations). Laser arrangement and fastening within transportation means should provide its steady position transportation. Laser displace during transportation is not allowed.
14. WARRANTY
1. Unless otherwise specified, all laser systems or components manufactured by LOTIS TII are warranted against defects in workmanship and materials for a period of twelve month from the date of delivery.
2. All optical components and crystals are warranted against defects in workmanship and materials for a period of 90 days from the date of delivery.
3. Damage of optics and crystals through misuse or mishandling is not covered under warranty.
4. Realignment and cleaning of lasers is not covered under warranty. This service will be billed even during the warranty period.
5. Warranty liability is limited to the repair or replacement of any equipment that proves to be defective in the warranty period. LOTIS TII will not be liable for any costs incurred for the shipment of defective components or for consequential damages.
6. Warranty repairs will be carried out at the premises of LOTIS TII or its appointed agents. Warranty repairs will be carried out at the customers premises only at the LOTIS TII.
7. Equipment repaired or replaced under warranty is warranted for only remaining unexpired portion of the original warranty period, which was applicable to the repaired or replaced equipment.
8. The above warranties do not apply to any equipment not manufactured by LOTIS TII. In cases where such equipment forms part of a system supplied by LOTIS TII, the original manufacturer’s warranty will be extended to LOTIS TII customers.
9. This warranty does not cover any defects caused by accident, misuse, neglect, tampering with or attempted repair of the equipment other than by an authorised agent of LOTIS TII.
10. The use of spare parts not approved by LOTIS TII invalidates the above warranty.
LS-2136-E4 Instruction Manual 25
TEST SHEET
Nd:YAG laser model LS-2136-E4 Serial N_________
Parameters Value
Pulse energy FF, mJ
Pulse energy SH per channel, mJ
Pulse duration (FWHM) 0.5 , ns
Beam divergence 0.86, mrad
Polarization of SH radiation
Delay between pump lamp triggering and Q-switch triggering, s
Simmer duration, sec
/2 attenuator count for ELS-02 operation
1.8xtelescope count, mm
Tested Minsk
LS-2136-E4 Instruction Manual 26
APPLICATION
Attenuator ( /2) transmittance
0 2 4 6 8 100
10
20
30
40
50
60
70
80
90
100
2
1
E/E 0,%
N(microscrew), mm
1 – corresponds to the mark “1” on the /2 holder 2 - corresponds to the mark “2” on the /2 holder
