Thorlabs Inc.
Visit the InGaAs Amplified Photodetector with Thermoelectric Cooler page for pricing and availability information

InGaAs Amplified Photodetector with Thermoelectric Cooler

  • Sensitive from 0.9 to 2.57 µm
  • Built-In TEC Reduces Thermal Noise
  • 8-Step Variable Gain and Bandwidth

PDA10DT

Post Not Included

Side Mounted
Post Not Included

PDA10DT

Side View,
Post Not Included

Power Supply Included with Detector

Hide Overview

OVERVIEW

MIR Photodetector Selection Guidea
Item # (Detector) Wavelength
Range
Maximum
Bandwidth
Thermoelectric
Cooler
PDA10DT (InGaAs) 0.9 - 2.57 µm 1 MHz Yes
PDA10D2 (InGaAs) 0.9 - 2.6 µm 25 MHz No
PDA10PT (InAsSb) 1.0 - 5.8 µm 1.6 MHz Yes
PDA07P2 (InAsSb) 2.7 - 5.3 µm 9 MHz No
PDAVJ8 (HgCdTe) 2.0 - 8.0 µm 100 MHz No
PDAVJ10 (HgCdTe) 2.0 - 10.6 µm 100 MHz No
PDAVJ5 (HgCdTe) 2.7 - 5.0 µm 1 MHz No
  • See the Cross Reference tab for our full selection of photodetectors.
PDA10DT SM1 Threads
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Close-Up of SM1 Threading Around Detector Element
PDA10DT with SM1 Lens Tube
Click to Enlarge

SM1L30C Lens Tube Attached to Detector Housing

Features

  • Sensitive to Mid-IR (MIR) Light from 0.9 - 2.57 µm
  • Max Bandwidth of Detector Package: 1 MHz
  • Built-In Thermoelectric Cooler Improves Sensitivity
  • Ø1 mm Detector Element
  • Post Mountable in Two Orientations
  • Internally SM1 (1.035"-40) Threaded
  • Location-Specific Power Adapter Included

Thorlabs' PDA10DT(-EC) Amplified Detector is a thermoelectrically cooled, photoconductive, extended-range InGaAs (indium gallium arsenide) detector. It is sensitive to light in the mid-IR spectral range from 0.9 to 2.57 µm. Two rotary switches control the gain amplifier and detector package bandwidth, allowing performance to be optimized for a variety of applications. The gain switch features eight discrete steps from 0 - 70 dB, while the bandwidth switch provides eight discrete steps from 500 Hz - 1 MHz. The thermoelectric cooler (TEC) uses a thermistor feedback loop to hold the temperature of the detector element at -10 °C, minimizing thermal contributions to the output signal. For best results, we recommend connecting the BNC output cable (not included) to a 50 Ω termination.

PDA10DT Side View
Click to Enlarge

Side View Showing Gain and Bandwidth Adjusters
PDA10DT Top View
Click to Enlarge

Top View Showing Signal Output and Power Input

The detector package incorporates many of the same mechanical features as our other mounted photodetectors. An internal SM1 (1.035"-40) threading allows Ø1" lens tubes to be mounted in front of the detector element, as shown to the right. Two 8-32 (M4 in the -EC version) tapped holes connect a Ø1/2" post to the housing in one of two perpendicular orientations, as shown in the image at the top of the page. The PDA10DT(-EC) includes a 100 - 240 VAC power adapter. If you require a different adapter plug, please contact Tech Support prior to ordering. An SM1RR Retaining Ring is also included.

Please note that inhomogeneities at the edges of the active area of the detector can generate unwanted capacitance and resistance effects that distort the time-domain response of the output. Thorlabs therefore recommends that the incident light is well centered on the active area. The SM1 (1.035"-40) threading on the housing can be connected to an SM1 lens tube; the lens tube can be used to mount an iris or pinhole in front of the detector element. Because the detector package is flush with the front of the threading, optics and optomechanics cannot be attached directly to the housing.

In addition to the InGaAs detector sold here, Thorlabs manufactures thermoelectrically cooled InAsSb detectors with significantly broader wavelength sensitivity ranges. If a more compact detector housing is desired, we also offer room-temperature amplified photodetectors.


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SPECS

All values given below are for a 50 Ω load, unless otherwise stated.

Gain (High Z)c
0 dB 1.51 x 103 V/A ± 2%
10 dB 4.75 x 103 V/A ± 2%
20 dB 1.50 x 104 V/A ± 2%
30 dB 4.75 x 10 V/A ± 2%
40 dB 1.51 x 10 V/A ± 2%
50 dB 4.75 x 105 V/A ± 2%
60 dB 1.50 x 106 V/A ± 2%
70 dB 4.75 x 10 V/A ± 2%

c. The gain for a 50 Ω impedance is one-half of the gain for high Z.

Noise-Equivalent Power (NEP) Valuesd
0 dB 15.9 pW/Hz1/2  @ DC - 2 MHz
10 dB 8.27 pW/Hz1/2 @ DC - 1.5 MHz
20 dB 2.8 pW/Hz1/2 @ DC - 700 kHz
30 dB 1.68 pW/Hz1/2 @ DC - 250 kHz
40 dB 1.33 pW/Hz1/2 @ DC - 150 kHz
50 dB 1.88 pW/Hz1/2 @ DC - 20 kHz
60 dB 2.22 pW/Hz1/2 @ DC - 7 kHz
70 dB 2.11 pW/Hz1/2 @ DC - 2.5 kHz

d. Measured at λP with a 1 MHz bandwidth and a 50 Ω impedance.

Item # PDA10DT(-EC)
Optical Specifications
Wavelength Range 0.9 - 2.57 μm
Peak Wavelength (λP) 2.3 μm
Peak Responsivity 1.3 A/W (Typ.) at Peak Wavelength
Electrical Specifications
Gain Settings 0, 10, 20, 30, 40, 50, 60, or 70 dB
(8 Steps)
Bandwidth Settings 0.5, 1, 5, 10, 50, 100, 500, or 1000 kHz
(8 Steps)
Output Voltagea 0 - 5 V at 50 Ω
0 - 10 V at High Z
Output Impedance 50 Ω
Output Current 100 mA (Max)
Load Impedance 50 Ω to High Z
Output Offsetb 20 mV (Typ.)
45 mV (Max)
Offset Drift 2.7 mV/°C (at 70 dB Gain)
Bias Voltage -2 V (at 0 dB and 10 dB Gain)
0 V (All Other Gain Settings)
Thermoelectric Cooler Specifications
TEC Temperature -10 °C
TEC Current 0.6 A (Typ.)
0.8 A (Max)
Thermistor 10 kΩ
Physical Specifications
Detector Element Extended Range InGaAs
Active Area 0.8 mm2
(Ø1.0 mm)
Surface Depth 0.08" (2.0 mm)
Output BNC
Detector Size 3" × 2.2" × 2.2"
(76.2 mm × 55.9 mm × 55.9 mm)
Weight Detector: 0.42 lbs (191 g)
Power Supply: 0.82 lbs (372 g)
Power Supply 30 W, Location-Specific
Power Cord Included
Input Power 100 - 120 VAC, 50 - 60 Hz
(-EC Version: 220 - 240 VAC)
Storage Temperature 0 to 85 °C
Operating Temperature 0 to 30 °C
  • Saturation of the output voltage may cause damage to the InGaAs detector element.
  • Quoted for 10 dB gain setting.

Hide Graphs

GRAPHS

PDA10DT SensitivityClick to Enlarge
Click to Download Raw Data
The graph above is for the 0 dB gain setting, and the shaded region denotes the detector's wavelength range.

PDA10DT Filter Bandwidth
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The graph above is for the 0 dB gain setting.
PDA10DT Gain Bandwidth
Click to Enlarge
The graph above is for the 1 MHz bandwidth setting.

Hide Pin Diagrams

PIN DIAGRAMS

Output Signal

BNC Female

BNC Female

0 - 5 V at 50 Ω
0 - 10 V at High Z
100 mA Max Current

Power Input

4-Pin Female

BNC Female
PinConnection
1 -12 V
2 Ground
3 +5 V
4 +12 V

Hide Cross Reference

CROSS REFERENCE

The following table lists Thorlabs' selection of photodiodes, photoconductive, and pyroelectric detectors. Item numbers in the same row contain the same detector element.

Photodetector Cross Reference
Wavelength Material Unmounted
Photodiode
Mounted
Photodiode
Biased
Detector
Amplified
Detector
Amplified Detector,
OEM Package
200 - 1100 nm Si FDS010 SM05PD2A
SM05PD2B
DET10A2 PDA10A2 PDAPC5
Si - SM1PD2A - - -
240 - 1170 nm Black Si FDBS11 SM05PD9A - - -
Black Si FDBS22 SM05PD8A DET20X2 - -
320 - 1000 nm Si - - - PDA8A2 -
320 - 1100 nm Si FD11A SM05PD3A - PDF10A2 -
Si - a - DET100A2a PDA100A2a PDAPC2a
340 - 1100 nm Si FDS10X10 - - - -
350 - 1100 nm Si FDS100
FDS100-CALb
SM05PD1A
SM05PD1B
DET36A2 PDA36A2 PDAPC1
Si FDS1010
FDS1010-CALb
SM1PD1A
SM1PD1B
- - -
400 - 1000 nm Si - - - PDA015A2
FPD310-FS-VIS
FPD310-FC-VIS
FPD510-FC-VIS
FPD510-FS-VIS
FPD610-FC-VIS
FPD610-FS-VIS
-
400 - 1100 nm Si FDS015c - - - -
Si FDS025c
FDS02d
- DET02AFC(/M)
DET025AFC(/M)
DET025A(/M)
DET025AL(/M)
- -
400 - 1700 nm Si & InGaAs DSD2 - - - -
500 - 1700 nm InGaAs - - DET10N2 - -
0.6 - 16 µm LiTaO3 - - - PDA13L2e -
750 - 1650 nm InGaAs - - - PDA8GS -
800 - 1700 nm InGaAs FGA015 - - PDA015C2 -
InGaAs FGA21
FGA21-CALb
SM05PD5A DET20C2 PDA20C2
PDA20CS2
-
InGaAs FGA01c
FGA01FCd
- DET01CFC(/M) - -
InGaAs FDGA05c - - PDA05CF2 PDAPC6
InGaAs - - DET08CFC(/M)
DET08C(/M)
DET08CL(/M)
- -
InGaAs - - - PDF10C2 -
800 - 1800 nm Ge FDG03
FDG03-CALb
SM05PD6A DET30B2 PDA30B2 -
Ge FDG50 - DET50B2 PDA50B2 PDAPC8
Ge FDG05 - - - -
900 - 1700 nm InGaAs FGA10 SM05PD4A DET10C2 PDA10CS2 -
900 - 2600 nm InGaAs FD05D - DET05D2 - -
FD10D - DET10D2 PDA10D2 PDAPC7
950 - 1650 nm InGaAs - - - FPD310-FC-NIR
FPD310-FS-NIR
FPD510-FC-NIR
FPD510-FS-NIR
FPD610-FC-NIR
FPD610-FS-NIR
-
1.0 - 5.8 µm InAsSb - - - PDA10PT(-EC) -
2.0 - 8.0 µm HgCdTe (MCT) VML8T0
VML8T4f
- - PDAVJ8 -
2.0 - 10.6 µm HgCdTe (MCT) VML10T0
VML10T4f
- - PDAVJ10 -
2.7 - 5.0 µm HgCdTe (MCT) VL5T0 - - PDAVJ5 -
2.7 - 5.3 µm InAsSb - - - PDA07P2 PDAPC9
  • If you are interested in purchasing the bare photodiode incorporated in these detectors without the printed circuit board, please contact Tech Support.
  • Calibrated Unmounted Photodiode
  • Unmounted TO-46 Can Photodiode
  • Unmounted TO-46 Can Photodiode with FC/PC Bulkhead
  • Pyroelectric Detector
  • Photovoltaic Detector with Thermoelectric Cooler

Hide Photodiode Tutorial

PHOTODIODE TUTORIAL

Photodiode Tutorial

Theory of Operation

A junction photodiode is an intrinsic device that behaves similarly to an ordinary signal diode, but it generates a photocurrent when light is absorbed in the depleted region of the junction semiconductor. A photodiode is a fast, highly linear device that exhibits high quantum efficiency and may be used in a variety of different applications.

It is necessary to be able to correctly determine the level of the output current to expect and the responsivity based upon the incident light. Depicted in Figure 1 is a junction photodiode model with basic discrete components to help visualize the main characteristics and gain a better understanding of the operation of Thorlabs' photodiodes.

Equation 1
Photodiode Circuit Diagram
Figure 1: Photodiode Model

Photodiode Terminology

Responsivity
The responsivity of a photodiode can be defined as a ratio of generated photocurrent (IPD) to the incident light power (P) at a given wavelength:

Equation 2

Modes of Operation (Photoconductive vs. Photovoltaic)
A photodiode can be operated in one of two modes: photoconductive (reverse bias) or photovoltaic (zero-bias). Mode selection depends upon the application's speed requirements and the amount of tolerable dark current (leakage current).

Photoconductive
In photoconductive mode, an external reverse bias is applied, which is the basis for our DET series detectors. The current measured through the circuit indicates illumination of the device; the measured output current is linearly proportional to the input optical power. Applying a reverse bias increases the width of the depletion junction producing an increased responsivity with a decrease in junction capacitance and produces a very linear response. Operating under these conditions does tend to produce a larger dark current, but this can be limited based upon the photodiode material. (Note: Our DET detectors are reverse biased and cannot be operated under a forward bias.)

Photovoltaic
In photovoltaic mode the photodiode is zero biased. The flow of current out of the device is restricted and a voltage builds up. This mode of operation exploits the photovoltaic effect, which is the basis for solar cells. The amount of dark current is kept at a minimum when operating in photovoltaic mode.

Dark Current
Dark current is leakage current that flows when a bias voltage is applied to a photodiode. When operating in a photoconductive mode, there tends to be a higher dark current that varies directly with temperature. Dark current approximately doubles for every 10 °C increase in temperature, and shunt resistance tends to double for every 6 °C rise. Of course, applying a higher bias will decrease the junction capacitance but will increase the amount of dark current present.

The dark current present is also affected by the photodiode material and the size of the active area. Silicon devices generally produce low dark current compared to germanium devices which have high dark currents. The table below lists several photodiode materials and their relative dark currents, speeds, spectral ranges, and costs.

Material Dark Current Speed Spectral Range Cost
Silicon (Si) Low High Speed Visible to NIR Low
Black Silicon (B-Si) Low Medium Speeda Visible to NIR Moderate
Germanium (Ge) High Low Speed NIR Low
Indium Gallium Arsenide (InGaAs) Low High Speed NIR Moderate
Indium Arsenide Antimonide (InAsSb) High Low Speed NIR to MIR High
Extended Range Indium Gallium Arsenide (InGaAs) High High Speed NIR High
Mercury Cadmium Telluride (MCT, HgCdTe) High Low Speed NIR to MIR High
  • While B-Si photodiodes are typically slower than Si, they feature higher responsivities across the wavelength range.

Junction Capacitance
Junction capacitance (Cj) is an important property of a photodiode as this can have a profound impact on the photodiode's bandwidth and response. It should be noted that larger diode areas encompass a greater junction volume with increased charge capacity. In a reverse bias application, the depletion width of the junction is increased, thus effectively reducing the junction capacitance and increasing the response speed.

Bandwidth and Response
A load resistor will react with the photodetector junction capacitance to limit the bandwidth. For best frequency response, a 50 Ω terminator should be used in conjunction with a 50 Ω coaxial cable. The bandwidth (fBW) and the rise time response (tr) can be approximated using the junction capacitance (Cj) and the load resistance (RLOAD):

Equation 3

Noise Equivalent Power
The noise equivalent power (NEP) is the input signal power that results in a signal-to-noise ratio (SNR) of 1 in a 1 Hz output bandwidth. This is useful, as the NEP determines the ability of the detector to detect low level light. In general, the NEP increases with the active area of the detector and is given by the following equation:

Photoconductor NEP

Here, S/N is the Signal to Noise Ratio, Δf is the Noise Bandwidth, and Incident Energy has units of W/cm2. For more information on NEP, please see Thorlabs' Noise Equivalent Power White Paper.

Terminating Resistance
A load resistance is used to convert the generated photocurrent into a voltage (VOUT) for viewing on an oscilloscope:

Equation 4

Depending on the type of the photodiode, load resistance can affect the response speed. For maximum bandwidth, we recommend using a 50 Ω coaxial cable with a 50 Ω terminating resistor at the opposite end of the cable. This will minimize ringing by matching the cable with its characteristic impedance. If bandwidth is not important, you may increase the amount of voltage for a given light level by increasing RLOAD. In an unmatched termination, the length of the coaxial cable can have a profound impact on the response, so it is recommended to keep the cable as short as possible.

Shunt Resistance
Shunt resistance represents the resistance of the zero-biased photodiode junction. An ideal photodiode will have an infinite shunt resistance, but actual values may range from the order of ten Ω to thousands of MΩ and is dependent on the photodiode material. For example, and InGaAs detector has a shunt resistance on the order of 10 MΩ while a Ge detector is in the kΩ range. This can significantly impact the noise current on the photodiode. For most applications, however, the high resistance produces little effect and can be ignored.

Series Resistance
Series resistance is the resistance of the semiconductor material, and this low resistance can generally be ignored. The series resistance arises from the contacts and the wire bonds of the photodiode and is used to mainly determine the linearity of the photodiode under zero bias conditions.

Common Operating Circuits

Reverse Biased DET Circuit
Figure 2: Reverse-Biased Circuit (DET Series Detectors)

The DET series detectors are modeled with the circuit depicted above. The detector is reverse biased to produce a linear response to the applied input light. The amount of photocurrent generated is based upon the incident light and wavelength and can be viewed on an oscilloscope by attaching a load resistance on the output. The function of the RC filter is to filter any high-frequency noise from the input supply that may contribute to a noisy output.

Reverse Biased DET Circuit
Figure 3: Amplified Detector Circuit

One can also use a photodetector with an amplifier for the purpose of achieving high gain. The user can choose whether to operate in Photovoltaic of Photoconductive modes. There are a few benefits of choosing this active circuit:

  • Photovoltaic mode: The circuit is held at zero volts across the photodiode, since point A is held at the same potential as point B by the operational amplifier. This eliminates the possibility of dark current.
  • Photoconductive mode: The photodiode is reversed biased, thus improving the bandwidth while lowering the junction capacitance. The gain of the detector is dependent on the feedback element (Rf). The bandwidth of the detector can be calculated using the following:

Equation 5

where GBP is the amplifier gain bandwidth product and CD is the sum of the junction capacitance and amplifier capacitance.

Effects of Chopping Frequency

The photoconductor signal will remain constant up to the time constant response limit. Many detectors, including PbS, PbSe, HgCdTe (MCT), and InAsSb, have a typical 1/f noise spectrum (i.e., the noise decreases as chopping frequency increases), which has a profound impact on the time constant at lower frequencies.

The detector will exhibit lower responsivity at lower chopping frequencies. Frequency response and detectivity are maximized for

Photoconductor Chopper Equation


Hide InGaAs Detector with TEC: 0.9 - 2.57 µm

InGaAs Detector with TEC: 0.9 - 2.57 µm

Item # PDA10DT(-EC)
Click Image to Enlarge PDA10DT
Detector Material
(Click for Image)
Extended Range InGaAs
Wavelength Range (λP) 0.9 - 2.57 µm
Peak Wavelength 2.3 µm
Peak Responsivity 1.3 A/W (Typ.) at Peak Wavelength
Active Area 0.8 mm2
(Ø1.0 mm)
Window Material Borosilicate Glass
Gain Settings 8 Steps: 0, 10, 20, 30,
40, 50, 60, or 70 dB
Bandwidth Settings 8 Steps from 500 Hz to 1 MHz
Noise-Equivalent Power (NEP) 2.11 pW/Hz1/2 @ DC - 2.5 kHz
(for 70 dB Gain and
1 MHz Bandwidth)

More detailed specifications are available in the Specs tab.

  • Sensitive to Mid-IR Light from 0.9 µm to 2.57 µm
  • Detector is Cooled to -10 °C to Reduce Thermal Noise
  • 0.8 mm2 Active Area (Ø1.0 mm)
  • Variable Gain Amplifier (1.51 kV/A to 4750 kV/A)
  • Variable Bandwidth (500 Hz to 1 MHz)
  • Internal SM1 (1.035"-40) Threading
  • Location-Specific Power Adapter Included
PDA10DT Sensitivity
Click to Enlarge

Click Here to Download Raw Data
The graph above is for the 0 dB gain setting, and the shaded region denotes the detector's wavelength range. 
PDA10DT Bandwidth
Click to Enlarge
The graph above is for the 0 dB gain setting.

Part Number
Description
Price
Availability
PDA10DT-EC
InGaAs Amplified Detector with TEC, 0.9 - 2.57 µm, DC-Coupled Amplifier, Ø1 mm, 100 - 240 VAC
$2,381.77
Lead Time
PDA10DT
InGaAs Amplified Detector with TEC, 0.9 - 2.57 µm, DC-Coupled Amplifier, Ø1 mm, 100 - 240 VAC
$2,381.77
Lead Time