Becker & Hickl GmbH
Becker & Hickl GmbH
August 2004
Printer HP 4500 PS
High Performance
Photon Counting
BDL-375
’Tel.
+49 / 30 / 787 56 32
FAX
+49 / 30 / 787 57 34
http://www.becker-hickl.com
email: info@becker-hickl.com
BDL-405 BDL-475
Ultraviolet and Blue Picosecond Diode Laser Modules
General
The BDL-375, BDL-405 and BDL-475 are picosecond laser diode modules with an emission
wavelengths in the range of 371-380 nm, 401-410 nm, and 468-478 nm [1,2]. Pulse repetition rates
of 20 MHz, 50 MHz, and 80 MHz can be selected. The maximum cw output power at 50 MHz is
typically 0.2 to 0.8 mW for the BDL-375 and -475, and 0.4-1.6 mW for the BDL-405. The
maximum peak power of the pulses is approximately 125 mW for the BDL-375 and -475, and up to
500 mW for the BDL-405.
The BDL laser modules have a TTL controlled shutdown input that can be used to switch the laser
off and on within a time of 1 us. The shutdown input can be used to multiplex several lasers of
different wavelength or to minimise sample exposure by activating the laser only during the
measurement time interval [5,6].
The BDL-405 and BDL-375 lasers are operated from a simple +12 V power supply. Emission
indicator LEDs and a key switch are in a box inserted in the power supply cable. The driving
generator is incorporated in the laser module.
The BDL laser modules are targeted at spectroscopy applications in combination with timecorrelated single photon counting (TCSPC) [3-8]. Their high repetition rate, multiplexing capability
and exceptionally low RF radiation make the BDL laser modules an ideal choice for a wide variety
of fluorescence lifetime, single molecule detection, lifetime microscopy, and fluorescence
correlation applications.
1
Picosecond Operation of Laser Diodes
Picosecond pulsing of laser diodes requires to drive extremely short current pulses trough the pn
junction of the diode. Unfortunately commercial laser diodes are not designed for this kind of
operation. Particularly, the junction capacitance Cj and the lead inductance Ll form an LC low pass
filter that impedes a fast voltage rise across the diode junction. The situation is shown in the figure
below.
For low driving power the generator pulse initiates a damped sine-wave voltage across the diode
junction. When the first positive peak reaches the forward conducting voltage of the diode, current
starts to flow through the junction. As long as the laser threshold is not reached the light pulse is
weak and broader than the current pulse.
If the driving power is increased the first positive peak drives a substantial forward current through
the diode junction. The dynamic impedance of the junction drops dramatically, preventing the
voltage at the junction to increase much above the forward voltage. The current through the junction
exceeds the laser threshold for a short fraction of the sine wave period, and a short light pulse is
emitted.
If the driving power is increased further the forward current pulse and consequently the light pulse
becomes stronger. Because the dynamic resistance of the pn junction decreases the pulse width
decreases. Eventually, the subsequent peaks of the sine wave start to drive a forward current through
the diode junction resulting in a tail in the light pulse or afterpulses.
Generator
Rg
Ll
Laser
Diode
Ij
Vg
Cj
Vj
Vg
Generator Voltage
Vj
Voltage accross
Laser Diode
Junction
Ij
Current through
Laser Diode
Junction
Light
Emission
Junction voltage Vj and junction current Ij in a picosecond laser diode for different driving pulse amplitude Vg
2
The behaviour of the junction current explains why there is a relation between the pulse quality and
the pulse power. Good pulse shapes can be obtained only at relatively low power. Taking a stronger
diode does not help. It actually makes the situation worse because the junction capacitance is higher.
Basically some improvement can be achieved by DC-biasing the laser diode in reverse direction and
using a correspondingly higher driving pulse amplitude. However, laser diodes have a very low
permissible reverse voltage which easily can be exceeded in the first negative half-period of the
junction voltage. For blue laser diodes, which have a forward conducting voltage of 4 to 5 V, the
driving amplitude is relatively high. This results in a correspondingly high reverse voltage in the
negative half-period. To achieve safe operation at high pulse power the diodes are operated at zero
or even positive (forward) bias. The influence of the diode bias is shown in the figure below.
Generator
Rg
Ll
Laser
Diode
Ij
Vg
Cj
Vj
V bias
Generator Voltage
Vg
Vj
Voltage accross
Laser Diode
Junction
Bias 3
Bias 2
Bias 1
Ij
Current through
Laser Diode
Junction
Light
Emission
Junction voltage Vj and junction current Ij in a picosecond laser diode for different diode bias voltage
It should be noted that the operating conditions of picosecond pulsed laser diodes are different from
those of modulated laser diodes used in communication equipment. A modulated laser diode is
always forward biased, and there is a continuous forward current through the laser diode.
Consequently, the diode junction has a low dynamic impedance that shorts the junction capacitance.
The speed of the diode is then determined mainly by the lead inductance and the generator
impedance.
Average Power and Peak Power
The typical pulse width for a picosecond laser diode is of the order of 100 ps or less. For a repetition
rate in the 20 to 80 MHz range the duty factor is of the order of 300. As shown in the figure below,
the result is an relatively high peak power even for low average (cw) power.
3
Pp
peak power
Pp = Pa
Tper
Tpw
Tpw
Pa
average power
Tper
Relation between peak power, average power, pulse width and pulse period
The peak power for all ps diode lasers is far beyond the permissible steady state power for the used
laser diodes. Due to the short pulse width this is tolerable to a certain extend. However, damage
effects in laser diodes are extremely fast and highly nonlinear. For the BDL-405 and BDL-375 we
recommend not to exceed an average power of 0.3 mW, 1 mW and 1.0 mW for 20 MHz, 50 MHz
and 80 MHz respectively for a longer period of operation.
Pulse Shape
Pulse shapes for a BDL-405 laser for different average power at 50 MHz are shown in the figure
below.
50 MHz, 0.4 mW
FWHM = 127 ps
50 MHz, 0.8 mW
FWHM = 84 ps
50 MHz, 1.2 mW
FWHM = 62 ps
50 MHz, 1.6 mW
FWHM = 52 ps
Pulse shapes for a BDL-405 laser at 50 MHz. Recorded with Hamamatsu R3809U-50 MCP [8] and BH SPC-730
TCSPC module [5].
The curves were recorded with a Hamamatsu R3809U-52 MCP PMT and a bh SPC-730 TCSPC
module. The R3809U-52 was operated at 3 kV yielding an instrument response function (IRF) of
30 ps fwhm.
The pulse width continuously decreases with the output power. The best pulse shape for 80 MHz,
50 MHz, and 20 MHz is obtained at 1.6 mW, 1 mW, and 0.4 mW, respectively. Typical curves of
the peak power and the pulse width are shown in the figure below.
4
600
mW
500
Peak
Power
Pulse
Width
Pulse
Width
Peak
Power
400
100
ps
300
fwhm
200
50
100
0
0.2
0.4
0.6
0.8
1.0
1.2
average (CW equivalent) power
1.4
1.6 mW
Pulse width and peak power for a BDL-405 versus average power at 50 MHz repetition rate. Pulse width corrected for
30ps IRF width of detection system.
The figure below shows the pulse shape for a BDL-475 laser for different average power at
50 MHz.
50 MHz, 100 µW
FWHM = 100 ps
50 MHz, 250 µW
FWHM = 50 ps
50 MHz, 400 µW
FWHM = 46 ps
50 MHz, 600 µW
FWHM = 45 ps
Pulse shapes for a BDL-475 laser at 50 MHz. Recorded with Hamamatsu R3809U-50 MCP and BH SPC-730 TCSPC
module.
Typical curves of the peak power and the pulse width are shown in the figure below.
100
ps
200
mW
Peak
Power
Pulse
Width
Peak
Power
100
0
Pulse
Width
fwhm
50
100
200
300
400
500 uW
average (CW equivalent) power
0
Pulse width and peak power for a BDL-475 versus average power at 50 MHz repetition rate. Pulse width corrected for
30ps IRF width of detection system.
5
Trigger Skew
The trigger pulse is derived directly from the output of the laser diode driver. It therefore appears
almost simultaneously with the light pulse. For measurements with the bh SPC modules, please use
a trigger cable that is 1 m to 3 m longer that the detector cable. This compensates for the delay in the
detector and places the stop pulse behind the end of the recorded time interval [5]. The trigger delay
does not change appreciably for different output power and for different repetition rate. The shift in
the light pulse with the power referred to the trigger pulse is shown in the figure below. The
repetition rate is 50 MHz, the power varies from 0.3 mW to 1.3 mW.
Shift of the light pulse with the output power referred to the trigger pulse. Left to
right: Power 0.3 mW, 0.5 mW, 0.8 mW and 1.3 mW
On-Off Behaviour
The BDL lasers can be switched on and off by applying TTL/CMOS signal to pin 7 of the sub-D
connector. TTL Low or connecting the pin to GND switches the laser off. When TTL Low is
applied the optical output and the trigger output shut down almost instantaneously. With TTL High
the laser resumes normal operation within 1 us. The switching behaviour is shown in the figure
below. 40 µs TTL high pulses were applied to the /laser on input, and the sequence was
accumulated for 105 pulses in the Scan Sync Out mode of an SPC-730 TCSPC module. The photons
were detected by an R3809U-52 MCP-PMT. Each curve of the sequence represents an interval of
1 µs.
On-off behaviour of the BDL lasers. 40 µs TTL high pulses were applied to the /laser on input. Each curve of the
sequence represents an interval of 1 µs. SPC-730 TCSPC module with R3809U MCP-PMT.
6
Operating the BDL-375, BDL-405 and BDL-475 laser modules
Adjusting the Collimator
The collimator can be adjusted laterally by loosening the four screws shown in the figure below.
Collimator screws
turn loose to shift
collimator laterally
Turn collimator to
adjust focus
Focus adjustment is done by turning the collimator lens assembly in its mounting thread.
Note: Please do not loosen the plastic screw left and right of the collimator. The screws hold the
peltier cooling assembly inside the laser. Loosening them can cause thermal damage to the laser
diode.
The standard focal length of the collimator lens is 8 mm. This gives a relatively large beam
diameter, as can be seen from the figure above (parallel beam 1 m from laser). The long focal length
results in a low divergence of the parallel beam. By changing the adjustment of the collimator lens
of the laser, the beam can be directly focused into a spot as close as 10 cm from the laser, or a
divergent beam can be obtained. The elliptical beam profile of the laser diode itself results in noncircular cross section of the beam. Nevertheless, the beam can be focused into a near-diffraction
limited spot. If a more circular beam cross section is needed, e.g. for efficient illumination of a
microscope lens, a anamorphotic lens or prism pair should be used to correct the shape.
Typical applications of different beam configurations are shown below. A parallel beam is used for
focusing on distant objects, and for focusing by a microscope objective lens designed for infinite
conjugate foci, i.e. for microscopes with a tube lens. A convergent beam can be used to focus
directly into a small spot or to compress the beam diameter by a single concave lens. A divergent
beam can be useful for beam expansion, and for focusing by a microscope objective lens designed
for use at conjugate foci, i.e. for microscopes without a tube lens.
Laser
Laser
Lens
Focusing on distant objects
Laser
Lens
Beam expansion by a single lens
Beam compression by a single lens
Laser
Laser
Microscope lens
Laser
Focusing through a microscope lens
(corrected for infinite conjugate ratio)
Microscope lens
Cuvette
Focusing into short distance
Focusing through a microscope lens
(corrected for finite conjugate ratio)
Beam patterns for different collimator adjustment and typical applications
The range of beam parameters that can typically be obtained is shown in the table below.
7
Collimator Adjustment
Focus distance
Divergence
mradian
Beam cross-section
at collimator output
Convergent beam
min. 10 cm
max. 45 x 18
4.5 x 1.8 mm
Parallel beam
-
< 0.1
4.5 x 1.8 mm
Divergent beam
min. -10 cm
max. -45 x -18
4.5 x 1.8 mm
Increase of beam
diameter over 1m
< 0.1 mm
Laser safety regulations demand for a special adjustment tool and a beam stop for class 3B lasers.
Please do not make any collimator adjustments on operating class 3B lasers with tools other than
specified.
Note: Please do not loosen the plastic screws left and right of the collimator. The screws hold the
heat sink of the peltier cooling assembly inside the laser. Loosening them can cause thermal damage
to the laser diode and the peltier cooler.
Caution: Light emitted by the device may be harmful to the human eye. Please pay attention to
safety rules when operating the devices. Avoid exposure to the laser beam, and not look into the
collimated beam. For wavelengths exceeding 650 nm the light intensity may be much higher than it
appears to the eye. In particular, laser safety forbids adjusting the collimator of class 3B lasers when
the lasers are switched on unless a special protecting tool is used. Please see section ‘Laser Safety’.
Input and Output Signals
The rear side of the BDL laser is shown in the figure below.
Power & Control
Trigger Out
Laser On
Cooling High
Power
Cooling Active
Bias
Power and Control Inputs
1
2
3
4
5
6
7
8
not connected
Frequency 20 MHz
Frequency 50 MHz
Frequency 80 MHz
GND
not connected
/Laser Off
Pulser supply test output
9
10
11
12
13
14
15
Laser diode bias test output
+12V Power supply input
not connected
External bias input
Temperature test output
not connected
GND
8
Pin 2,3,4, Frequency
Frequency select pins. The laser works with the specified frequency if the corresponding pin is at
TTL/CMOS High or open. Tie the pins of the unused frequencies into GND or use the ‘Frequency’
switch in the laser switch box inserted in the power supply cable.
Pin 5, Ground
Reference pin for all signals and power supply ‘-’ pin.
Pin 7, /Laser Off
Connecting this pin to TTL/CMOS Low or GND switches the laser off. The laser beam is shut
down and the trigger output becomes inactive. After disconnecting the pin from GND or switching
to TTL/CMOS ‘high’ the laser resumes normal operation within 1 us. Leave the pin open if you
want the laser to run continuously. The /Laser Off signal is used to switch off the laser during the
beam flyback in laser scanning microscopes. Please notice that the laser does not deliver trigger
pulses when it is switched off by /Laser Off = ‘low’. For a connected bh TCSPC modules this is no
problem. However, if the /Laser Off signal is pulsed at a high rate the SPC module will display a
SYNC rate lower than the actual value.
Pin 8, Pulser supply test output
Pin 8 is a test output. It delivers the internal power supply voltage of the driving generator.
Depending on the power, the voltage at pin 8 is between +5V and +6.9V. Do not connect this pin.
Pin 9, Laser diode bias test output
Pin 9 is a test output. It delivers the diode bias voltage. Please note that the diode is forward biased,
i.e. the power increases with increasing bias voltage. Do not connect this pin.
Pin 10, Power supply input
Pin 10 is the power supply input. The nominal power supply voltage is +12 V. The laser works in a
range of +9V to +15 V. The power supply current may vary between about 300 mA and 1.5 A. Most
of the input power is used for temperature stabilisation of the laser diode. Therefore the power
supply current varies with the temperature and with the time after switch-on.
Important note: For reasons of laser safety the BDL laser modules must be operated with the
power supply cable delivered with the modules and the box containing the switch box and the
emission indicators.
Pin 12, External bias input
Pin 12 is an external diode bias input. An input voltage in the range of -10 V to +10 V changes the
bias of the laser diode. Positive inputs increase the diode bias and increase the output power. The
external bias voltage is added to the bias voltage set by the ‘diode bias’ potentiometer.
Pin 13, Temperature test output
This pin delivers an output from the temperature regulation amplifier. The voltage is typically 1 V
to 1.5 V after switch on and drops to 100 mV to 200 mV after the laser diode temperature has
stabilised.
Trigger Output
The trigger pulse is derived directly from the output of the laser diode driver. It therefore appears
almost simultaneously with the light pulse. For measurements with the bh SPC modules, please use
a trigger cable that is 1 m to 3 m longer that the detector cable. This compensates for the delay in the
detector and places the stop pulse behind the end of the recorded time interval.
9
The trigger pulse is positive and has a pulse width of about 1 ns. The amplitude depends on the
power and is about 100 to 200 mV. If you use the BDL lasers with a bh SPC module, please use the
A-PPI adapter to invert the trigger pulse.
Power and Diode Bias Adjust
There are two potentiometers at the back of the laser module. The ‘Power’ adjust changes the
operating voltage of the driving generator. The ‘Bias’ adjust changes the bias voltage of the laser
diode. Higher voltage and higher bias give higher output power. The best pulse shape is obtained
with minimum bias and moderate power. We recommend to turn the ‘Bias’ adjust screw until the
power is at minimum and then to adjust the desired power and pulse shape with the ‘Power’ screw.
Please see also section ‘Picosecond Operation of Laser Diodes’.
LED Indicators on the Laser
The left LED flashes when the power of the laser is on and the ‘/Laser Off’ signal is ‘high’ or
unconnected.
The right LED is on when the cooling of the laser diode is active. It may turn off after some time of
operation when the diode has been cooled down and almost no cooling power is required to hold it
at constant temperature.
The red LED in the middle turns on when the cooling power is at maximum. It should turn off after
some minutes of operation.
Power Supply Cable for the Class 3R and Class 3B Lasers
The BDL laser modules are operated from a simple +12V wall-mounted AC-DC-adapter power
supply. For reasons of laser safety the ‘Laser Switch Box’ shown below is inserted in the power
supply cable from the AC-DC adapter to the laser. The switch box contains a key switch, several
parallel ‘power on’ or emission indicator LEDs of different colour, and one LED that indicates that
the laser is switched off via the /laser off signal. The /laser off signal and an analog power control
signal can be connected to SMA connectors at the back of the switch box.
The 15 pin connector at the laser side can be used as a ‘remote interlock connector’. The connector
can be pulled off or plugged in at any time without causing damage to the laser.
SMA connectors:
Shutdown
1)
Analog Power Control
Repetition Rate Switch
’Remote Interlock Connector’
+12V in
from wall-mounted
AC-DC power adapter
15 Pin Sub D
Connector
connected to
laser module
9 Pin
Sub-D
Connector
Key Switch
1) Analog power control changes the power only within the range specified for the laser
Laser switch box with key switch, emission indicator LEDs and control inputs
10
Laser Safety
The BDL-375 is a class 3B, the BDL-405 and BDL-475 are 3R laser products. The laser class is
indicated on the laser by an ‘explanatory label’, see figure below.
BDL-375 (UV)
BDL-405 and BDL-475 (visible)
The laser aperture is marked with the aperturere label and the hazard warning label shown below.
Moreover, each laser has a manufacturer label. The label specifies the type, the wavelength and
repetition rate, and the certification of the laser. An example for the BDL-405 laser is shown below.
The position of the labels on the laser modules is shown in the figures below.
Manufacturer label (white, left)
and explanatory label (yellow,
right)
Aperture label (on top of the laser)
and laser hazard labels (left and
right of the aperture)
Caution: Laser safety regulations forbid the user to open the housing of the laser, or to do any
maintenance or service operations at or inside the laser. Use of controls or adjustments or
performance of procedures other than specified herein may result in hazardous radiation exposure or
damage to the laser module.
If the collimator of a class 3B laser has to be adjusted, the laser has to be turned off during
adjustment, or a special adjustment tool has to be used. Please contact bh.
Moreover, do not look into the laser beam through lenses, binoculars, magnifiers, camera finders,
telescopes, or other optical elements that may focus the light into your eye. When using the lasers in
combination with a microscope make sure that the beam path to the eyepieces is blocked when the
laser is on.
11
Application to Fluorescence Lifetime Spectroscopy
Fluorescence Lifetime Experiments
A simple setup for general fluorescence lifetime experiments is shown below.
+12V from AC/DC Adapter
A-PPI Adapter
Trigger to SPC
BDL-405 Laser
+12V to PMH
SPC-630, 730 or 830 TCSPC Module
Fluorescence
Sample Cell
PMH-100 PMT Module
Detector Signal
Electronic components and system connections for fluorescence lifetime experiments
The electronic setup consists of the BDL-405 laser module, an SPC-630, -730 or -830 TCSPC
module and a PMH-100 detector module [5]. An A-PPI adapter is used to connect the trigger output
of the laser to the SYNC input of the SPC module. The PMH-100 gets its power supply from the
SPC module.
With an optical setup consisting of a few lenses and filters the system can be used for highsensitivity fluorescence lifetime experiments. Please note that blue and NUV laser diodes emit a
substantional amount of background light in a wide wavelegnth range. It is therefore important to
place a cleaning filter in the excitation light path.
Laser Scanning Microscopy and Related Applications
In combination with a confocal microscope, fluorescence correlation measurements [11-14] and
fluorescence lifetime imaging [15-18] are possible. A typical setup for fluorescence lifetime
imaging with a confocal laser scanning microscope is shown below. Blue and NUV laser diodes
have been proved to be applicable to laser scanning microscopy and ophthalmologic imaging
[18-20].
12
PMH-100
R3809U
b&h
SPC-830 TCSPC Imaging Module
200ps
<50ps
Fibre Output
Detector
start
stop
BDL-405
Scanning
Head
+12V
Scanning Microscope
Zeiss LSM 510
Leica SP 2
Biorad Radiance, etc.
Microscope
Control
Box
Pixel Clock, Line Clock, Frame Clock
Fluorescence lifetime imaging with confocal laser scanning microscope
The required power in the focus of the microscope objective is less than 50 µW. However, in
scanning microscopes the back aperture of the objective is over-illuminated to obtain a uniform
intensity distribution over the whole aperture. This gives maximum spatial resolution for a given
numerical aperture of the objective, but wastes most of the laser power. If the BDL lasers are used at
a scanning microscope the beam geometry should be checked and, if necessary, a beam expander
optics be used to obtain the optimum beam diameter. With an available power of the order of
500 µW a reasonable compromise between the power in the focal plane and the spatial resolution
can be achieved.
Multiplexing BDL Laser Modules
Multiplexing of several laser modules can be used to record fluorescence decay curves or lifetime
images quasi-simultaneously for several excitation wavelengths. The principle is shown in the
figure below.
SPC module records individual curves for both lasers
Lasers multiplexed via /shautdown signals
100 Hz to 10 kHz
TRG Out
BDL
/off
power combiner
SYNC
TRG Out
BDL
/off
Routing
bh TCSPC module
Multiplexing BDL laser modules
Several laser modules are switched on sequentially by controlling the /shutdown inputs in a way that
only one laser is active at a time. On the detection side the routing capability of the BH TCSPC
modules is used. Simultaneously with the switching of the lasers the control logic sends a routing
signal to the TCSPC module that directs the recorded photons into different memory blocks. Laser
multiplexing can be used in conjunction with multi-detector operation [4-8]. The synchronisation
signal for the TCSPC module is generated via a passive power combiner (a reversed power splitter).
The TCSPC module delivers separate waveforms (fluorescence decay curves, time-of-flight
distributions, etc.) for the different lasers. Due to the short switch-on time of the laser multiplexing
rates in the 10 to 100 kHz range can be obtained.
13
Compared to a pulse-by-pulse multiplexing the pulse group multiplexing technique shown above
has the benefit that the effective stop rate of the TCSPC module is not reduced. Because the
maximum count rate of the TCSPC technique is proportional to the effective TAC stop rate pulse
group multiplexing allows to run the experiment at higher count rate. Please see [5,6] for details.
14
Specification
Optical
BDL-375
Repetition Rate
Wavelength typical, nm
375
Wavelength, min - max, nm
371-380
Pulse Width (FWHM, Power 0.5 mW, 50 MHz)
Peak Power, max, mW 1)
125
Optical Power 2)
mW, 20 MHz
0.1 to 0.3
(Average CW power, mW, 50 MHz
0.2 to 0.8
adjustable)
mW, 80 MHz
0.3 to1.0
Stability of Repetition Rate
Pulse-to Pulse Jitter
Power and pulse shape stabilisation after ‘Laser on’ signal
Power and pulse shape stabilisation after switch-on
BDL-405
Trigger Output
473
468-478
125
0.1 to 0.3
0.2 to 0.8
0.3 to1.0
all lasers
Pulse Amplitude
Pulse Width
Output Impedance
Connector
Delay from Trigger to Optical Pulse
Jitter between Trigger and Optical Pulse
+100 mV (peak) into 50 Ω
1 ns
50 Ω
SMA
< 500 ps
< 10 ps
Control Inputs
all lasers
Frequency 20 MHz 3)
Frequency 50 MHz 3)
Frequency 80 MHz 3)
/Laser Off 3)
External Bias Input
TTL / CMOS high
TTL / CMOS high
TTL / CMOS high
TTL / CMOS low
analog input, -10 V to + 10V
Power Supply
Power Supply Voltage
Power Supply Current
BDL-475
20-50-80 MHz, selectable
405
401-410
60 to 90 ps
500
0.16-0.6
0.4-1.6
0.6-2.5
± 100 ppm
< 10 ps
1 µs
3 min
all lasers
+ 9 V to +12 V
300 mA to 1 A
4)
Mechanical Data
Dimensions
Mounting Thread
all lasers
160 mm x 90 mm x 60 mm
two M6 holes
Maximum Values
Power Supply Voltage
Voltage at Digital Control Inputs
Voltage at Ext. Bias Input
Ambient Temperature
all lasers
0 V to +15 V
-2 V to +7 V
-12 V to + 12 V
0 °C to 30 °C 5)
1) Typical values, sample tested. Depends on pulse width and selected power.
2) Recommended power adjust range. Lower power gives broader pulses, higher power gives ringing in pulse shape. Power levels
above the given range can be selected, but are not guaranteed and may impair the lifetime of the laser diode.
3) All inputs have 10 kΩ pull-up resistors. Open input is equivalent to logic ‘high’.
4) Dependent on ambient temperature. Cooling current changes due to temperature regulation of laser diode
5) Operation below 13 °C may result in unstable power or extended warm-up time.
Caution: Light emitted by the device may be harmful to the human eye. Please pay attention to safety rules when
operating the devices. Do not look into the collimated laser beam.
15
References
[1] S. Nakamura, S.F.Chichibu, Introduction to nitride semiconductor blue lasers and light emitting diodes. Taylor &
Francis (2000)
[2] S. Nakamura, M.Senoh, S. Nagahama, N. Iwasa, T. Matsushita, T. Mukai, InGaN/GaN/AlGaN-based LEDs and
laser diodes. MRS Internet Journal of Nitride Semiconductor Research, 4s1, 1.1. (1999)
[3] D.V. O’Connor, D. Phillips, Time Correlated Single Photon Counting, Academic Press, London 1984
[4] W. Becker, A. Bergmann, H. Wabnitz, D. Grosenick, A. Liebert, High count rate multichannel TCSPC for optical
tomography. Proc. SPIE 4431(2001) 249-254
[5] SPC-134 through SPC-730 TCSPC Modules, Operating Manual and TCSPC Compendium. Becker & Hickl GmbH,
www.becker-hickl.com
[6] Wolfgang Becker, Axel Bergmann, Controlling TCSPC Experiments. www.becker-hickl.com
[7] Routing Modules for Time-Correlated Single Photon Counting, Becker & Hickl GmbH, www.becker-hickl.com
[8] 16 Channel Detector Head for Time-Correlated Single Photon Counting, Becker & Hickl GmbH,
www.becker-hickl.com
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