Light Conversion ORPHEUS User manual
ORPHEUS User’s Manual
PREFACE
This manual contains user information for the non-collinear optical parametric amplifier ORPHEUS.
Please read this manual first before attempting to connect and/or operate ORPHEUS. Special
attention should be paid to the “Safety precautions” chapter, which describes the safety measures that
should be taken while using the device. Always use the instrument only for its intended purpose and as
described in the manual. Failing to do so may void the instruments warranty and compromise user’s safety.
This manual is intended to give the user thorough description of the operation of ORPHEUS, guidance
on daily usage of the device and troubleshooting advice in case of problems. The manual assumes that the
ORPHEUS has been installed by a qualified service engineer. The user is strongly advised not to attempt to
perform a new installation or re-installation of ORPHEUS by following this manual.
Information in this manual is believed to be accurate and reliable. All information in this document is
subject to change without notice. In no event will Light Conversion be liable for any direct or indirect
damages resulting from any defects in this documentation. Always consult Light Conversion Support Team
or your service engineer, if you have doubts about any instructions written in the manual before acting.
Thank you for using Light Conversion products.
The latest WinTOPAS software version
Download the latest WinTOPAS software version from Light Conversion website www.lightcon.com:
Go to “Support” → “OPA Software Update” for the download link. No login required.
ORPHEUS User’s Manual
TABLE OF CONTENTS
PREFACE......................................................................................................................................................3
TABLE OF CONTENTS ..................................................................................................................................5
List of Figures ......................................................................................................................................7
List of Tables .......................................................................................................................................7
SAFETY SIGNAL WORDS AND SIGNS...........................................................................................................8
1. SAFETY PRECAUTIONS........................................................................................................................9
1.1 Optical Safety .........................................................................................................................9
1.2 Electrical Safety ....................................................................................................................10
1.3 Warning and Information Labels..........................................................................................10
2. ELECTRICAL AND PHYSICAL SPECIFICATIONS ...................................................................................12
2.1 Dimensions...........................................................................................................................12
2.2 Description of Input and Output Ports.................................................................................13
3. PUMP REQUIREMENTS.....................................................................................................................14
4. POSITIONING AND CONNECTING ORPHEUS ....................................................................................15
4.1 System Layout on Optical Table ...........................................................................................15
4.2 Fixing ORPHEUS on the Optical Table ..................................................................................15
4.3 Beam Routing Units..............................................................................................................17
4.4 Connecting ORPHEUS...........................................................................................................17
4.5 Input Beam Shutter ..............................................................................................................19
4.6 Interlock ...............................................................................................................................20
5. DESCRIPTION OF OPERATION ..........................................................................................................21
5.1 Overview ..............................................................................................................................21
5.2 Pump Beam Delivery and Splitting.......................................................................................23
5.3 White Light Continuum Generator.......................................................................................23
5.4 Generation of the Second Harmonic of Pump .....................................................................23
5.5 First Amplification Stage ......................................................................................................24
5.5.1 The First Pass....................................................................................................................24
5.5.2 The Second Pass ...............................................................................................................25
5.6 Second Amplification Stage..................................................................................................26
5.7 Output polarization ..............................................................................................................27
5.8 Wavelength Separators........................................................................................................27
5.9 Computer Controllable Motorized Stages............................................................................28
5.10 Computer Control of ORPHEUS............................................................................................29
6. DAILY OPERATION ............................................................................................................................30
6.1 Setting the Wavelength........................................................................................................30
6.2 Optimizing the Output .........................................................................................................30
7. OPTIMIZATION OF ORPHEUS PERFORMANCE .................................................................................31
7.1 Checking Pump Laser Parameters........................................................................................31
7.2 Resetting Motor Positions....................................................................................................32
7.3 Input Beam Alignment .........................................................................................................32
7.4 Damage of Sapphire Substrate in White Light Generation Path..........................................33
7.5 Adjusting the Pump Intensity for White Light Generation ..................................................34
7.6 Adjusting the Pump Intensity for the First Amplification Stage...........................................35
7.7 Applying Offsets for the Calibration Curve ..........................................................................35
8. MAINTENANCE .................................................................................................................................37
8.1 General Maintenance...........................................................................................................37
8.2 Handling of Nonlinear Crystals.............................................................................................37
9. TROUBLESHOOTING GUIDE..............................................................................................................38
9.1 White Light Generation Does Not Occur/Is Instable............................................................38
9.2 Low Parametric Output or No Output at All ........................................................................38
ORPHEUS User’s Manual
9.3 Low Second Harmonic Generation Efficiency...................................................................... 38
10. DISPOSAL...................................................................................................................................... 39
10.1 Dismantling the System ....................................................................................................... 39
10.2 Disposal................................................................................................................................ 39
ORPHEUS User’s Manual
List of Figures
Figure 1. Location of the labels on the ORPHEUS body ...................................................................................10
Figure 2. ORPHEUS housing dimensions and positions of input and output ports (mm)................................12
Figure 3. Location of input and output ports on the ORPHEUS body..............................................................13
Figure 4. Recommended layout of ORPHEUS with an external Signal pulse compressor and pump laser .....15
Figure 5. Location of the three balls on which the device rests ......................................................................16
Figure 6. Positioning the feet of ORPHEUS on the optical table (SI system) ...................................................16
Figure 7. Positioning the feet of ORPHEUS on the optical table (Imperial system).........................................16
Figure 8. Location of the adjustment screws on the beam routing unit..........................................................17
Figure 9. Connectors of ORPHEUS....................................................................................................................18
Figure 10. The main USB control board of ORPHEUS ......................................................................................18
Figure 11. ORPHEUS extension plates (A or B) and shutter connector (C) ......................................................18
Figure 12. Shutter external view from input side and principle of operation .................................................19
Figure 13. Interlock defeat procedure .............................................................................................................20
Figure 14. Layout of the ORPHEUS subunits ....................................................................................................21
Figure 15. Optical layout of ORPHEUS .............................................................................................................22
Figure 16. View of the first amplification stage from above............................................................................24
Figure 17. View of the first amplification stage from the side.........................................................................24
Figure 18. A closer look at the amplified seed beam exiting the first amplification stage after the second
pass. Yellow is the amplified beam, White –WLC, Green –pump ..................................................................25
Figure 19. Location of the manual Delay 3 adjustment protective screw .......................................................26
Figure 20. Wavelength separator (WS) with and without metal cover ...........................................................27
Figure 21. Location and names of the motorized stages inside ORPHEUS......................................................28
Figure 22. Apertures inside ORPHEUS and placement of beam alignment targets during input beam
alignment. ........................................................................................................................................................33
Figure 23. Illustration showing a key inserted into the axial adjustment hole in the WLG adapter. ..............34
Figure 24. No white light generation (a) and very low intensity of white light (b) are indications that there is
too little energy in the pulse, or the beam is focused improperly onto the crystal ........................................34
Figure 25. Low (a), medium (b) and high (b) intensity of white light generated in sapphire substrate by 1030
nm radiation.....................................................................................................................................................35
List of Tables
Table 1. Safety signal words and safety signs used in this manual....................................................................8
Table 2. Location and description of ORPHEUS labels .....................................................................................11
Table 3. Electrical and utility requirements .....................................................................................................12
Table 4. Physical specifications ........................................................................................................................12
Table 5. Description of ORPHEUS input/output ports .....................................................................................13
Table 6. ORPHEUS output polarizations...........................................................................................................27
Table 7. List of wavelength separators ............................................................................................................28
Table 8. Names and descriptions of the motorized stages inside ORPHEUS...................................................28
ORPHEUS User’s Manual
SAFETY SIGNAL WORDS AND SIGNS
The following safety signal words and safety signs are used throughout this manual:
Table 1. Safety signal words and safety signs used in this manual
Safety sign
Signal word
Description
DANGER
Indicates a hazardous situation that, if not avoided, will result in
death or serious injury.
WARNING
Indicates a hazardous situation that, if not avoided, could result in
death or serious injury.
CAUTION
Indicates a hazardous situation that, if not avoided, could result in
minor or moderate injury.
NOTICE
Indicates information considered important, but not hazard-related
(e.g. relating to property damage).
Indicates danger of electrical hazard to personal safety.
Indicates danger of exposure to hazardous laser radiation.
ORPHEUS User’s Manual
1. SAFETY PRECAUTIONS
This section should be carefully reviewed prior to operating the ORPHEUS optical parametric
amplifier (OPA). Safety precautions contained herein and throughout the manual must be carefully
followed to ensure that all personnel who operate the laser and the OPA are protected from accidental
exposure to laser radiation and high voltage.
WARNING
ORPHEUS, when coupled with an appropriate pump laser,
comprises a Class 4 laser product. Avoid eye or skin exposure
to direct or scattered radiation. It may cause skin injuries,
eye damage with possible blindness, and could also
constitute a fire hazard.
ORPHEUS, when coupled with an appropriate pump laser, comprises a Class 4 laser product that
poses safety hazards if not used properly. Produced direct or scattered radiation can cause permanent eye
damage and possible blindness, skin injuries. Beams can be powerful enough to burn skin, clothes, or ignite
fire and can also damage light sensitive optical equipment such as video cameras, photodiodes, etc. It is
imperative that users learn all safety information, which is provided in the pump laser’s manuals.
1.1 Optical Safety
Maximum accessible radiation level from the ORPHEUS. The used and emitted power/pulse energy
by ORPHEUS may vary upon the type and model of pump laser used. The average input power may be
20 W, with pulse duration ranging from 100 to 300 fs. Emitted radiation can be over 20 W, 2 mJ and 10-
300 fs pulse width. The wavelengths emitted by/present in ORPHEUS are: 1030 nm, 515 nm, 620-3000 nm.
Additional frequency mixers extend the tunable range to 210 nm to 20 µm. Be very careful when aligning
and working with ORPHEUS.
WARNING
Avoid viewing the beam and specular reflections. Always
wear protective eyewear when aligning and operating the
ORPHEUS. Ensure your protective glasses cover all
wavelengths emitted by the laser system.
User is advised to follow the precautions below:
1. Always wear protective eyewear. Choose protective eyewear appropriate to wavelength and
intensity of the radiation, conditions of use, and visual function required. Remember that the
ORPHEUS output wavelength can be automatically and continuously tuned in broad wavelength
range.
2. Never look directly into the laser beam or scattered laser light from any reflective surface.
3. Avoid wearing watches, jewelry and other objects that may reflect or scatter the laser beam.
4. Set up the laser system so that laser beam paths are located well below eye level. Keep the
beams enclosed where possible.
5. Use energy absorbing targets and shields for beam blocking and preventing unnecessary
reflections or scatter.
6. Avoid blocking the laser beam or its reflection with any part of your body.
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7. Limit access to the laser system to qualified personnel only, who have received appropriate
safety laser training and are aware of dangers involved.
8. Use the laser system in a closed room. Laser light remains collimated over long distances and
therefore presents a potential hazard if not confined.
9. Do not work with ORPHEUS cover opened unless necessary. Intense light beams, their specular
and scattered reflections can be emitted from various parts of ORPHEUS when the cover is
opened.
10. Always keep the ORPHEUS powered for the safety beam shutter to operate correctly.
11. Post warning signs near the laser operation area.
1.2 Electrical Safety
1. Disconnect the power supply when working on any electrical equipment when it is not
necessary for the equipment to be operating.
2. Do not connect or disconnect any cables with the power supply connected to the mains
electricity.
3. Never work on electrical equipment unless there is another person nearby who is familiar with
the operation and hazards of the equipment, and who is competent to administer first aid.
4. The equipment must only be connected to a mains electricity with protective earth to avoid risk
of electrical shock.
WARNING
To avoid the risk of electrical shock, this equipment must
only be connected only to a mains electricity with protective
earth.
1.3 Warning and Information Labels
Description of ORPHEUS labels is presented in Figure 1 and Table 2.
Figure 1. Location of the labels on the ORPHEUS body
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Table 2. Location and description of ORPHEUS labels
No.
Label
Location and description
1
Manufacturer identification label is located on the
side of the ORPHEUS housing.
2
Device identification label is located on the side of
the ORPHEUS base below Manufacturer label.
3
Warning logotype is located on the side of the
ORPHEUS.
4
Aperture label is located next to the output aperture
of the ORPHEUS and points to it.
5
Label for defeatably interlocked housing is located
on the removable parts of the protective housing.
6
Laser radiation warning logo is located at every input
and output port of the housing.
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2. ELECTRICAL AND PHYSICAL SPECIFICATIONS
For indoor use only!
ORPHEUS is powered by external power supply provided by the manufacturer. Contact “Light
Conversion”support team before using a power supply from other manufacturers.
Table 3. Electrical and utility requirements
Power requirements (external power supply)
Voltage: 100–240 VAC
Frequency: 50/60 Hz
Max. current: 1.6 A
Power requirements (control board)
Voltage: 24 VDC
Max. current: 5 A
Altitude
Up to 2500 m
Operating temperature
15-40 °C
Relative humidity
10-70 % (non-condensing)
Table 4. Physical specifications
Length
590 mm
Width
230 mm
Height
163 mm
Weight
16 kg
Input/output port height
125 mm
Optical beam path length*
2.3 m
* From the input to the output port.
2.1 Dimensions
* Wavelength separator not pictured
Figure 2. ORPHEUS housing dimensions and positions of input and output ports (mm)
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2.2 Description of Input and Output Ports
Figure 3. Location of input and output ports on the ORPHEUS body
Figure 3 show the layout of ORPHEUS input and output ports. Parametric radiation is emitted from
the main output port A. Depending on the system configuration, some of the input/output ports may not
be used, but there may still be some radiation emitted from those apertures. They should be blocked
accordingly. Full description of input and output ports is presented in Table 5.
There are also many smaller holes on ORPHEUS body, which are used during alignment of the device.
They are not specially identified; however, it is possible that some radiation may leak through these
apertures. Therefore, make sure that every alignment aperture is closed during normal operation.
Table 5. Description of ORPHEUS input/output ports
No.
In/Out
Wavelength
Description
A
Output
620-2600 nm
Main output port of the ORPHEUS
B
Output
515 nm
Residual second harmonic of pump from the power amplification stage
C
Output
1030 nm
Residual fundamental pump
D
Input
1030 nm
Pump laser input into ORPHEUS
E
Input
1030 nm
Pump laser input into ORPHEUS
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3. PUMP REQUIREMENTS
Good performance of ORPHEUS requires high pump quality in terms of both time and space
coherence. This means that ideal pump is diffraction-limited beam and transform-limited, high contrast
pulse. To some extent, performance of ORPHEUS is an indicator of quality of the pump laser radiation.
In femtosecond systems that use nowadays-standard chirped pulse amplification technique (CPA),
there are specific possible causes of distorted beam or pulse. Some of them are discussed below.
Spatial beam quality. Non-uniformity of the beam reduces the energy conversion rate. Presence of
hot spots in the beam may cause small-scale self-focusing that in turn leads to phase modulation. In the
nonlinear crystals, hot spots can also produce parametric superfluorescence or white light generation.
Increasing the average power in such cases could lead to damage of the crystal or other optical
components.
Spatial/temporal beam distortion. In contrast to long pulse lasers, astigmatism introduced by
improperly aligned lenses of beam expanders/reducers lead to distortion of temporal profile of the pulse
across the beam. This makes it impossible to overlap pump and signal pulses over entire beam aperture in
ORPHEUS.
Tilted pulses. This phenomenon manifests itself in similar way as that discussed above. However, it
originates from improper pulse compressor alignment. Tilted pulses are produced when the angular
dispersion is not completely cancelled. The problem with this kind of distortion is that it can be easily
overlooked using standard diagnostics equipment such as autocorrelator.
Underseeded regenerative amplifiers. The seed pulses for regenerative amplifier can be too week
due to low oscillator power, poor mode matching or improper Pockel’s cell timing. This results in rather
high energy content in the background. Background can be undetectable either by oscilloscope or by
autocorrelator. Simple test for background is measurement of build-up time of unseeded and seeded
regenerative amplifier. In last case the build-up time should be shorter at least by 15-20%.
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4. POSITIONING AND CONNECTING ORPHEUS
4.1 System Layout on Optical Table
Figure 4 shows the recommended optical layout of ORPHEUS and pump laser. It is recommended to
position ORPHEUS along the side of optical table, about 5-20 cm from the table edge. Such a positioning
allows convenient access while aligning the device.
It is strongly recommended to fix all the system on the same optical table and as close as possible to
each other. Fixing the housings on a junction of the optical tables or letting the beam propagate several
meters until it enters ORPHEUS might increase the sensitivity of the system and/or lower the performance
especially in terms of long time scale instabilities.
Figure 4. Recommended layout of ORPHEUS with an external Signal pulse compressor
and pump laser
The beam from the amplifier is lifted to the input beam height level using a periscope. Depending on
the system layout, the periscope may direct the beam straight forward or at a 90 degree angle. Mirrors
BRM1 and BRM2 direct the beam to the ORPHEUS. The output beams exit the housing at the same height
as the input beam.
4.2 Fixing ORPHEUS on the Optical Table
ORPHEUS housing is fixed onto the optical table using special feet. The device freely rests on these
feet via three balls located on the ORPHEUS body. The feet are assembled into pads prepared for the width
and length of the ORPHEUS. They are fitted to the height of the pump beam and are not height adjustable.
The pads have 8 mounting holes each. Only two of them should be used for fixing to the optical
table. Figure 6 shows correct positioning of the feet on an optical table with 25 mm hole spacing. Figure 7
shows the correct positioning of the feet on an optical table with 1 inch hole spacing. Notice that in this
case, different mounting holes should be used.
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Figure 5. Location of the three balls on which the device rests
Figure 6. Positioning the feet of ORPHEUS on the optical table (SI system)
Figure 7. Positioning the feet of ORPHEUS on the optical table (Imperial system)
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Do not operate the system if either ORPHEUS or the pump laser is not fixed to the optical table. This
could lead to dangerous misalignment of ORPHEUS and damage of internal components.
4.3 Beam Routing Units
Depending on the model of the pump laser and system layout, it may be necessary to use periscopes,
beam splitters (BS) and/or beam routing mirrors (BRM) to deliver the pump beam into ORPHEUS. Optical
components of these items are put in metal enclosures designed for safety and stability. These enclosures
are prepared for specific beam heights but are flexible in terms of system layout.
Tuning the angle of the mirrors is done by micrometer screws accessible with a 2 mm hex key,
location of the screws is shown in Figure 8. It is recommended to use only vertical and horizontal screws for
alignment (not diagonal). Depending on the model of the units, the position can be locked by tightening the
locking screws.
Figure 8. Location of the adjustment screws on the beam routing unit
The periscope consists of two mirrors and only the top mirror is coarsely adjustable. This mirror
should be only adjusted once during the installation to keep the beam parallel to the optical table.
All enclosed beam routing units, periscope, and shutter are interconnected with hollow tubes to fully
enclose the beam path. This is necessary to ensure user safety and stability of the OPA output.
4.4 Connecting ORPHEUS
ORPHEUS needs to be connected to the power supply and to a computer to operate. Additionally, if
the system is supplied with water cooled beam dumps, water supply must be connected to the device. If
water is not available, beam dumps must be replaced with air-cooled alternatives.
ORPHEUS has three connection panels (Figure 9). The panel of the main circuit board for the power
supply and USB connection (Figure 10) is located on the side of ORPHEUS body. Shutter connector is
located on the front side. The connectors (extension plate) for external devices are located on the back
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side, below the output ports. In some configurations the main circuit board connections might be in front
of the ORPHEUS housing, below the attached beam routing mirror.
Figure 9. Connectors of ORPHEUS
Figure 10. The main USB control board of ORPHEUS
Figure 11. ORPHEUS extension plates (A or B) and shutter connector (C)
The sequence of connecting the ORPHEUS should be as follows:
1. Water cooling to the water-cooled beam blocks, if applicable.
2. External devices (Mixers, LYRA, etc.) to the extension plate.
3. Shutter cable to the dedicated shutter connector.
4. USB cable.
5. Power supply cable.
6. Install WinTOPAS from your USB flash disk.
7. Turn on the USB control board.
8. Install the control board driver as described in WinTOPAS user’s manual.
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NOTICE
Always make sure the USB control board is powered off
before connecting the extension cables.
Use only power supplies from Light Conversion. Power supply from Light Conversion is suitable to
both 110 V and 220 V outlets. Make sure that the main circuit board’s switch is in “OFF” position before
connecting the power supply.
WARNING
Always check that the supply and its cables are in proper
condition and do not show any damage to any part of the
insulation, before connecting.
It is recommended to install the WinTOPAS software before connecting ORPHEUS to computer.
Follow the instructions in the software start guide. Connect ORPHEUS to computer using supplied USB
cable.
Power LED (Red) should be always on and Status LED (Green) should blink with intervals of ~1 second
during normal operation of the USB control board. The software needs to be configured for a device,
hardware settings file must be linked in the software. Consult the WinTOPAS user’s manual on software
configuration.
A single computer can control up to 5 of the USB control boards. A USB-hub can be used if the
computer does not have enough USB ports. Light Conversion does not guarantee proper operation of
ORPHEUS with non-branded USB-hubs.
4.5 Input Beam Shutter
ORPHEUS is equipped with a stand-alone external shutter (see Figure 12a). Its primary purpose is to
enhance user safety while working with ORPHEUS. External shutter also safely dissipates the heat of the
input radiation.
a) b) c)
Figure 12. Shutter external view from input side and principle of operation
Principle of operation relies on HR1030 mirror placed on a rotary solenoid. When the solenoid is not
powered (turned off), the mirror is directing the input beam sideward into the air-cooled or water-cooled
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beam dump (Figure 12b). When power is supplied to the solenoid, the mirror is displaced out of the beam
path and the beam is passed through (Figure 12c). The red LED lights up when power is supplied to the
shutter. The WinTOPAS3 software displays the current state of the shutter and provides the control for
opening and closing it.
The software displays the current state of the shutter and provides the control for opening and
closing it (see WinTOPAS start guide).
WARNING
Always keep the control board powered for the shutter to
operate correctly and for the WinTOPAS to display correct
shutter status.
4.6 Interlock
ORPHEUS is equipped with an interlock mechanism. It is impossible to open the shutter when the
interlock is active. The interlock is activated when an electrical circuit is broken, which happens when
ORPHEUS cover is opened. This releases the button thus breaking the circuit.
CAUTION
Never work with ORPHEUS cover removed unless aligning
the device. Always pay close attention to safety precautions
detailed in this manual, documentation of the laser and
regulations in your laboratory.
To defeat the interlock, pull the button upwards.
Figure 13. Interlock defeat procedure
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