THORLABS PDF10A2 User manual

Femtowatt Photoreceiver
PDF10A2
Operation Manual
2020

Version:
Date: 1.0 10-Mar-2020
Copyright © 2020 Thorlabs

Foreword
Contents
1 General Information 1
11.1 Ordering Codes and Accessories
2 Getting Started 2
22.1 Parts List 22.2 Preparation
3 Operating Instruction 3
33.1 Operating Elements 33.2 Mounting 43.3 Operation 53.4 Recommendations 63.5 Operating Principle 63.5.1 Optical Input 63.5.2 Electrical Output
4 Maintenance and Service 7
5 Appendix 8
85.1 Technical Data 95.2 Typical Responsivity 95.3 Typical Frequency Response 105.4 Typical Spectral Noise 105.5 Typical Output Time Response 115.6 Drawings 115.7 Safety 125.8 Return of Devices 125.9 Manufacturer Address 135.10Certifications and Compliances 145.11Warranty 145.12Exclusion of Reliability and Copyright 155.13Thorlabs Worldwide Contacts and WEEE poilicy

© 2020 Thorlabs
We aim to develop and produce the best solutions for your
applications in the field of optical measurement techniques. To help
us to live up to your expectations and constantly improve our
products, we need your ideas and suggestions. We and our
international partners are looking forward to hearing from you.
Thorlabs GmbH
Warning
Sections marked by this symbol explain dangers that might result in
personal injury or death. Always read the associated information
carefully before performing the indicated procedure.
Please read this advice carefully!
This manual also contains "NOTES" and "HINTS" written in this form.
Attention
Paragraphs preceded by this symbol explain hazards that could
damage the instrument and the connected equipment or may cause
loss of data.
Note

© 2020 Thorlabs
1 General Information
1
1 General Information
This Thorlabs PDF10A2 Femtowatt Photoreceiver combines a low-noise silicon photodiode with
a specially designed ultra-low-noise, fixed-gain transimpedance amplifier with extremely high
gain of up to 1012 V/A. This combination results in a photoreceiver with femtowatt sensitivity and
an exceptionally low NEP, making it ideal for low-light level detection applications, such as
spectroscopy and fluorescence measurements. Direct detection of optical power down to ~10
fW is possible. In combination with an optional lock-in amplifier, sub-femtowatt sensitivity can
be achieved.
Due to a very high sensitivity, the PDF10A2 Femtowatt Photoreceiver can replace photomulti-
plier tubes (PMTs), avalanche photodiodes (APDs), and liquid-nitrogen-cooled germanium pho-
todiodes in many applications. No expensive high-voltage power supply or cooling is required.
Another advantage is that the PDF10A2 cannot be damaged by unwanted ambient light, which
is critical for many photomultiplier tubes.
The PDF10A2 detector housing can be integrated in optical setups using convenient 8-32 and
M4 combi-thread mounting holes that are compatible with both imperial and metric threading.
Please see the chapter Mounting for details.
The housing accommodates Thorlabs' SM05 (0.535"-40) and SM1 (1.035"-40) threaded adap-
ters and accessories. This allows convenient mounting of external optics, light filters, and aper-
tures. The product includes an SM1 Coupler Body (SM1T1), which adapts the external thread
to an internal thread and holds the SM1RR Retaining Ring, and a reusable protective plastic
cover cap. For accessories, please visit our website or contact Thorlabs .
A ±12 VDC power supply is included with each amplified photodetector. The appropriate input
voltage (100 VAC, 120 VAC, 230 VAC) can be selected with a switch on the power supply .
Attention
Please find all safety information and warnings concerning this product in the chapter Safety
in the Appendix.
1.1 Ordering Codes and Accessories
PDF10A2 Femtowatt Photoreceiver, Silicon detector, 320 - 1100nm, Bandwidth DC-20Hz,
Square Active Area 1.2 mm2 (1.1 mm x 1.1 mm), Combi-Thread Mounting Holes
Compatible with 8-32 and M4 Threads
Included Accessories
·LDS12B Power Supply (±12V, 0.2A), 100 VAC, 120 VAC or 230 VAC Line Voltage
·Plastic Cover Cap (Item # SM1EC2B) on an included SM1T1 SM1 Coupler with a SM1RR
SM1 Retaining Ring.
Optional Accessories
·All Thorlabs internal SM1 (1.035"-40) and external SM05 (0.535"-40) threaded accessories
are compatible with the PDF10A2.
·Fiber adapter of the Thorlabs S120-xx. These fiber adapter can be mounted on the optical in-
put for fiber coupled applications.
·PDA-C-72 DC power supply cable to PDF10A2: This cable has a connector on one end and
open wires at the other. The pin-out of the PDF10A2 DC power jack is shown in the ap-
pendix .
Please visit our homepage http://www.thorlabs.com for various accessories like fiber adapters,
posts and post holders, data sheets and further information.
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PDF10A2
2 Getting Started
2.1 Parts List
Please inspect the shipping container for damage. Do not cut through the cardboard. You might
need the box for storage or returns.
If the shipping container seems to be damaged, keep it until you have inspected the contents
mechanically and electrically.
Verify that you have received the following items within the package:
1. PDF10A2 Amplified Photodetector
2. Plastic Cover Cap (Item # SM1EC2B) on SM1T1-SM1 Coupler with an SM1RR-SM1 Re-
taining Ring
3. LDS12B Power Supply (±12V, 0.2A), 100 VAC, 120 VAC or 230 VAC Line Voltage
4. Quick Reference
2.2 Preparation
Carefully unpack the unit and accessories. If any damage is noticed, do not use the unit.
Contact Thorlabs and have us replace the defective unit.
Note
Prior to operation, please check if the indicated line voltage range on the power supply matches
with your local mains voltage! Adjust the power supply accordingly to 100 VAC, 120 VAC or
230 VAC.
Note
If you prefer to use your own power supply, please ask Thorlabs for an appropriate power
connector cable .
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© 2020 Thorlabs
3 Operating Instruction
3
3 Operating Instruction
3.1 Operating Elements
PDF10A2
3.2 Mounting
Housing
The PDF10A2 is housed in a rugged, shielded, 70.9 mm x 49.9 mm x 22.5 mm aluminum en-
closure.
Mounting PDF10A2 on an Optical Table
Mount the PDF10A2 on an optical post by using either of the two tapped mounting holes on the
side and bottom. The combi-thread tapped holes accept both 8-32 and M4 threads, such that
using either imperial or metric TR posts is possible.
Mounting External Optics
The PDF10A2 housing accommodates Thorlabs’ SM05-threaded (0.535"-40) and SM1-
threaded (1.035"-40) adapters that are compatible with any number of Thorlabs 1” and ½”
threaded accessories. This allows to mount external optics, filters, apertures, fiber adapters,
lens tubes, or cage systems. For accessories, please visit our website or contact Thorlabs .
The PDF10A2 comes with an SM1T1 SM1 coupler that adapts the external thread to an SM1
internal thread. A retaining ring in the coupler holds the protective cover cap. Please unscrew
the coupler if needed.
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PDF10A2
3.3 Operation
Attention
Ensure that the correct mains voltage is selected on the power supply prior to connecting the
power supply to the mains power. Wrong settings for the mains voltage may damage the power
supply. The ±12 V, 250 mA power supply is included; no high voltage power supply is required
for operation.
Attention
Refer to the Technical Data and pay attention to the optical damage threshold of 10 mW!
Exceeding this value will permanently destroy the detectors!
Attention
Due to limitations in the IC, the high-speed amplifier used in these devices may become un-
stable, exhibiting oscillations or negative output, if the power supply voltage is applied when the
module is on. Therefore, please make sure the power-on switch on your PDF10A2 is in OFF
position 0 (see Operating Elements ) prior to connecting the external power supply.
Electrical Setup
·Mount the detector using the combi-thread mounting holes on the side and bottom of the
device.
·Make sure the PDF10A2 is switched off.
·Plug the power connector cable into the DC INPUT LDS12B connector of the PDF10A2.
·Plug the power supply into an outlet.
·Connect OUTPUT to your data acquisition device with a coaxial cable. The PDF10A2 with
femtowatt sensitivity is a low-frequency device that should only be terminated into high impe-
dance (Hi-Z) loads.
·Switch on the power supply.
·Switch on the PDF10A2 by moving the power slider to I while the optical input is protected by
the cover cap.
·The maximum OUTPUT voltage swing is ±10 V for high impedance loads (>10 kW). The
OUTPUT signal should stay below this maximum output voltage to avoid amplifier saturation.
Optical Setup
·Ensure that OUTPUT offset voltage is within the range listed in Technical Data . A small
drift during the warm up period (~5 min) is typical.
·Check whether the noise level is below 5 mVRMS. If the noise level is significantly higher,
please refer to recommendations and optimize your setup.
·Remove the plastic cover cap that protects the optical input.
·Mount external optics if needed.
·Align the light source with the optical input.
·It is recommended to focus the optical signal out of the fiber onto the detector.
·To prevent saturation of the amplifier keep the optical input powers below the CW saturation
power listed in Technical Data . External neutral density filters or attenuators are recom-
mended to reduce the input light level in critical cases.
·For maximum linearity performance and to prevent damage to the detector when measuring
focused beams, fiber outputs, or small diameter beams, do not exceed a maximum input
power of 10 mW/cm2.
Turning off the PDF10A2
Move the power slider to 0after finishing the measurements.
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3 Operating Instruction
5
3.4 Recommendations
·Optical Alignment
oAn open beam should always be carefully aligned with the detector. Due to the small active
area of the PDF10A2 photodiodes, it is recommended to focus the optical signal out of a
fiber onto the detector. For this and other fiber-coupled applications, fiber adapters like
Thorlabs S120-xx series can be mounted on the optical input. The fiber adapters accom-
modate multi-mode or single-mode fibers.
oPlease note that coupling losses may occur due to the small detector size. This will result in
a reduced output signal. If angled connectors are used, an FC adapter can be rotated from
its original position to improve the alignment. For this process apply an input signal with
power below the saturation level while observing the output voltage using a digital voltmeter
or other low-frequency measurement device.
·Ambient or stray light
oPDF10A2 photodetectors are extremely sensitive devices. To reduce the noise level, careful
shielding of the PDF10A2 from any unwanted light sources is essential. Common tech-
niques are baffling or other opaque barriers like black cloths or beam tubes. Even a small
power-on indicator LED far away from the PDF10A2 can affect power measurements at
femtowatt levels.
oIt is not necessary to switch off the PDF10A2 when it is exposed to ambient light. The amp-
lifier will saturate but, unlike photomultiplier tubes, it will not be damaged or saturated for a
long period of time.
oIt is highly recommended to use appropriate bandpass filters in front of the detector to mini-
mize the influence of stray light.
·High Optical Input Power
oTo avoid permanent damage to the detector, do not exceed the specified optical damage
threshold of 10 mW as specified in section Technical Data .
oKeep the optical input power below the CW saturation power listed in the Technical Data
to avoid electrical saturation.
·Amplifier Saturation
To avoid electrical saturation of the amplifier keep the output voltage Vout below the maximum
listed in Technical Data . External neutral density filters or attenuators are recommended to
reduce the input light level in critical cases.
·Electrostatic Coupling
Electrostatic coupling of electrical noise associated with ground loops can be critical. In most
cases an electrically isolated post (e.g. Thorlabs item# TRE or TRE/M) will suppress elec-
trical noise coupling. Always try to identify electrical noise sources and increase the distance
to the PDF10A2. If possible, rotate the PDF10A2 input away from the noise source. Different
common ground points can also be tested.
·Impact of Temperature
oThe amplifier offset voltage is factory set to zero at 23 °C ambient temperature. Due to the
very high transimpedance gain, even small temperature changes or even humidity changes
may affect the offset voltage. Therefore it is recommended for precise DC light level mea-
surements to use the PDF10A2 in an environment with constant temperature after a short
warm up period (~5 min).
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PDF10A2
3.5 Operating Principle
The Thorlabs PDF10A2 Femtowatt Photoreceiver combines a low noise Silicon photodiode with
a specially designed ultra low noise transimpedance amplifier with extremely high gain. This
unique combination results in a photoreceiver with femtowatt sensitivity due to the exceptional
low NEP and makes it ideal for low-light level detection applications, such as spectroscopy and
fluorescence measurements. Direct detection of optical power down to ~10 fW is possible.
3.5.1 Optical Input
Optical Beam Alignment
The PDF10A2 uses a Silicon Photodiode with a square detector active area of 1.2 2 (1.1 mm x
1.1 mm).
Due to this small active area of the PDF10A2 photodiodes, it is recommended to focus the op-
tical signal out of the fiber onto the detector.
Because the housing is compatible with any number of Thorlabs 1” and ½” threaded accessor-
ies, external optics, filters or apertures can be easily attached to the PDF10A2.
Detector Sensitivity
The PDF10A2 and PDF10C2 are specified for determined wavelength ranges . The typical
responsivity curves can be found in the appendix . Please note that these femtowatt photore-
ceivers are extremely sensitive to unwanted stray light.
3.5.2 Electrical Output
Responsivity
The Thorlabs PDF10A2 detectors deliver an output voltage, which is a function of incident light
power POPT, detector responsivity Â(l) and transimpedance gain G given by:
l × ×OUT OPTV =P ( ) G
The responsivity Â(l) for a given wavelength can be read from the diagrams Typical Responsi-
vity to estimate the output voltage. Please note that transimpedance gain tolerance is ±10%
for an individual unit due to extremely high feedback resistors used for the transimpedance
amplifier. Temperature changes or even humidity changes may affect transimpedance gain.
Output Voltage
The maximum output voltage is 10 V for high impedance loads (>10 kW). The output signal
should stay below the maximum output voltage to avoid saturation. Depending on wavelength
responsivity Â(l) of the detector, the amplifier will reach saturation at optical input power greater
than CW Saturation Power listed in Technical Data .
Note
Typical curves for the Frequency Response , Spectral Noise Distribution and Output Time
Response can be found in the appendix.
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4 Maintenance and Service
7
4 Maintenance and Service
Protect the PDF10A2 from adverse weather conditions. The PDF10A2 is not water resistant.
Attention
To avoid damage to the instrument, do not expose it to spray, liquids or solvents!
The unit does not need a regular maintenance by the user. It does not contain any modules
and/or components that could be repaired by the user. If a malfunction occurs, please contact
Thorlabs for return instructions.
Do not remove covers!
Do not open the power supply unit!
Cleaning
To clean the PDF10A2 housing, use a mild detergent and damp cloth. Do not soak the unit in
water or use solvent based cleaners.
When cleaning the window of the photodetector, please remember that is a sensitive optical
device. Gently blow off any dust using compressed air and wipe gently with an optic tissue wet-
ted with isopropanol.
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PDF10A2
5 Appendix
5.1 Technical Data
Specification
PDF10A2
Detector Material
Silicon
Detector Wavelength Range
320 - 1100 nm
Typical Max. Responsivity
0.6 A/W @ 960 nm
Detector Active Area
1.2 mm2(1.1 mm x 1.1 mm)
Transimpedance Gain
1 x 1012 V/A ±10%
Max. Conversion Gain
0.6 x 1012 V/W ±10%
Output Bandwidth (3dB)
DC - 20 Hz
Rise/Fall Time (10% -90%)
22 ms
CW Saturation Power
16 pW
Max. Input Power
(Photodiode Damage Threshold))
10 mW
Minimum NEP (DC - 3dB bandwidth)
3.0 fW/ÖHz
Electrical Output, Impedance
BNC, 200 Ω
Maximum Output Voltage
10 V
DC-Offset Electrical Output
< ±75 mV
Size
70.9 mm x 49.9 mm x 22.5 mm
Power Supply
±12V, 250 mA
Operating Temperature Range
10°C to 50°C
Storage Temperature Range
-25°C to 70°C 2)
All technical data are valid at 23 ± 5°C and 45 ± 15% rel. humidity
2) non condensing

© 2020 Thorlabs
5 Appendix
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5.2 Typical Responsivity
PDF10A2 Typical Detector Responsivity
5.3 Typical Frequency Response
For the measurement of the frequency response, a test signal was fed through an optical chop-
per and fiber-coupled to the PDF10A2 input. The output voltage amplitude was measured with
an oscilloscope.
PDF10A2 Typical Frequency Response

© 2020 Thorlabs10
PDF10A2
5.4 Typical Spectral Noise
Noise is being characterized by different specifications. The spectral noise of PDF10A2 was
measured using a 200 kSample/s A/D converter. The power density spectrum was calculated
from the sampled values with respect to transimpedance gain and detector responsivity. The
optical input of the PDF10A2 was blocked.
Other noise specifications are the NEP (Noise Equivalent Power) and the overall RMS output
noise, specified for a defined bandwidth. These parameters are stated in Technical Data ).
PDF10A2 Typical Spectral Noise
5.5 Typical Output Time Response
Rise/fall time measurements were carried out with the same setup described in the typical fre-
quency response.
PDF10A2 Typical Output Time Response
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5 Appendix
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5.6 Drawings
Dimensions of PDF10A2
5.7 Safety
Attention
The safety of any system incorporating the equipment is the responsibility of the assembler of
the system.
All statements regarding safety of operation and technical data in this instruction manual will
only apply when the unit is operated correctly as it was designed for.
The PDF10A2 must not be operated in explosion endangered environments.
Do not remove covers. There are no user-serviceable parts inside.

© 2020 Thorlabs12
PDF10A2
This precision device is only serviceable if returned and properly packed into the complete ori-
ginal packaging including the cardboard insert that holds the enclosed devices. If necessary,
ask for replacement packaging. Refer servicing to qualified personnel.
Changes to this device cannot be made nor may components not supplied by Thorlabs be used
without written consent from Thorlabs.
Attention
Prior to applying power to the PDF10A2, make sure that the protective conductor of the 3 con-
ductor mains power cord is correctly connected to the protective earth ground contact of the
socket outlet! Improper grounding can cause electric shock resulting in damage to your health
or even death!
Ensure that the line voltage setting of the power supply agrees with your local supply and that
the corresponding fuses are inserted. If not, please change the line voltage setting (see section
Preparation ).
To avoid risk of fire, only the appropriate fuses for the corresponding line voltage must be used.
All modules must only be operated with duly shielded connection cables.
Users that change or modify the product described in this manual in a way not expressly ap-
proved by Thorlabs (party responsible for compliance) could void the user’s authority to operate
the equipment.
Thorlabs GmbH is not responsible for any radio television interference caused by modifications
of this equipment or the substitution or attachment of connecting cables and equipment other
than those specified by Thorlabs. The correction of interference caused by such unauthorized
modification, substitution or attachment will be the responsibility of the user.
The use of shielded I/O cables is required when connecting this equipment to any and all op-
tional peripheral or host devices. Failure to do so may violate FCC and ICES rules.
Attention
Mobile telephones, cellular phones or other radio transmitters are not to be used within the
range of three meters of this unit since the electromagnetic field intensity may then exceed the
maximum allowed disturbance values according to IEC 61326-1.
5.8 Return of Devices
This precision device is only serviceable if returned and properly packed into the complete ori-
ginal packaging including the complete shipment plus the cardboard insert that holds the en-
closed devices. If necessary, ask for replacement packaging. Refer servicing to qualified per-
sonnel.
5.9 Manufacturer Address
Manufacturer Address Europe
Thorlabs GmbH
Münchner Weg 1
D-85232 Bergkirchen
Germany
Tel: [phone]
Fax: [phone]
www.thorlabs.de
Email: [email protected]
EU-Importer Address
Thorlabs GmbH
Münchner Weg 1
D-85232 Bergkirchen
Germany
Tel: [phone]
Fax: [phone]
www.thorlabs.de
Email: [email protected]
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5 Appendix
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5.10 Certifications and Compliances

© 2020 Thorlabs14
PDF10A2
5.11 Warranty
Thorlabs warrants material and production of the PDF10A2 for a period of 24 months starting
with the date of shipment. During this warranty period Thorlabs will see to defaults by repair or
by exchange if these are entitled to warranty.
For warranty repairs or service the unit must be sent back to Thorlabs. The customer will carry
the shipping costs to Thorlabs, in case of warranty repairs Thorlabs will carry the shipping costs
back to the customer.
If no warranty repair is applicable the customer also has to carry the costs for back shipment.
In case of shipment from outside EU duties, taxes etc. which should arise have to be carried by
the customer.
Thorlabs warrants the hard- and/or software determined by Thorlabs for this unit to operate
fault-free provided that they are handled according to our requirements. However, Thorlabs
does not warrant a fault free and uninterrupted operation of the unit, of the software or firmware
for special applications nor this instruction manual to be error free. Thorlabs is not liable for
consequential damages.
Restriction of Warranty
The warranty mentioned before does not cover errors and defects being the result of improper
treatment, software or interface not supplied by us, modification, misuse or operation outside
the defined ambient stated by us or unauthorized maintenance.
Further claims will not be consented to and will not be acknowledged. Thorlabs does explicitly
not warrant the usability or the economical use for certain cases of application.
Thorlabs reserves the right to change this instruction manual or the technical data of the de-
scribed unit at any time.
5.12 Exclusion of Reliability and Copyright
Thorlabs has taken every possible care in preparing this document. We however assume no li-
ability for the content, completeness or quality of the information contained therein. The content
of this document is regularly updated and adapted to reflect the current status of the hardware
and/or software. We furthermore do not guarantee that this product will function without errors,
even if the stated specifications are adhered to.
Under no circumstances can we guarantee that a particular objective can be achieved with the
purchase of this product.
Insofar as permitted under statutory regulations, we assume no liability for direct damage, indir-
ect damage or damages suffered by third parties resulting from the purchase of this product. In
no event shall any liability exceed the purchase price of the product.
Please note that the content of this document is neither part of any previous or existing agree-
ment, promise, representation or legal relationship, nor an alteration or amendment thereof. All
obligations of Thorlabs result from the respective contract of sale, which also includes the com-
plete and exclusively applicable warranty regulations. These contractual warranty regulations
are neither extended nor limited by the information contained in this document. Should you re-
quire further information on this product, or encounter specific problems that are not discussed
in sufficient detail in the document, please contact your local Thorlabs dealer or system in-
staller.
All rights reserved. This document may not be reproduced, transmitted or translated to another
language, either as a whole or in parts, without the prior written permission of Thorlabs.
Copyright © Thorlabs 2020. All rights reserved.

© 2020 Thorlabs
5 Appendix
15
5.13 Thorlabs Worldwide Contacts and WEEE poilicy
For technical support or sales inquiries, please visit us at www.thorlabs.com/contact for our
most up-to-date contact information.
USA, Canada, and South America
Thorlabs, Inc.
[e-mail]
[e-mail]
UK and Ireland
Thorlabs Ltd.
[e-mail]
[e-mail]
Europe
Thorlabs GmbH
[e-mail]
Scandinavia
Thorlabs Sweden AB
[e-mail]
France
Thorlabs SAS
[e-mail]
Brazil
Thorlabs Vendas de Fotônicos Ltda.
[e-mail]
Japan
Thorlabs Japan, Inc.
[e-mail]
China
Thorlabs China
[e-mail]
Thorlabs 'End of Life' Policy (WEEE)
Thorlabs verifies our compliance with the WEEE (Waste Electrical and Electronic Equip-
ment) directive of the European Community and the corresponding national laws. Ac-
cordingly, all end users in the EC may return “end of life” Annex I category electrical and
electronic equipment sold after August 13, 2005 to Thorlabs, without incurring disposal
charges. Eligible units are marked with the crossed out “wheelie bin” logo (see right),
were sold to and are currently owned by a company or institute within the EC, and are
not dissembled or contaminated. Contact Thorlabs for more information. Waste treat-
ment is your own responsibility. “End of life” units must be returned to Thorlabs or
handed to a company specializing in waste recovery. Do not dispose of the unit in a litter
bin or at a public waste disposal site.

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