IR DETECTORS

A full range of photovoltaic (PV), and photoconductive (PC) infrared detectors are available. These detectors are made from semiconductiong materials which give high detectivity (D*) in the 0.7 - 20 micron spectral region.

 

LMS detectors have applications in the following fields:

  Infrared spectroscopy

  Thermal sensing

  CO2 laser detection

  Laser range-finding

  Thermal imaging arrays

  Position sensors (quadrants)

  Heterodyne signal detection

  Pollutant detection

  Gas monitoring

When selecting an LMS infrared detector, the following parameters should be taken into consideration:

  Spectral response - wavelength range to be measured

  Detector active area

  Bandwidth

  Window material

  Field-of-view

  Operating temperature and method of cooling

  Package type for the detector element.

LMS PV detectors are fabricated by diffusion or ion implantation techniques with shallow pn junctions and corresponding high quantum efficiencies. They also offer high speed of response, improved sensitive area uniformity, very low power dissipation and elimination of bias voltages.  

Photovoltaic detectors include:

Germanium (Ge)

Indium Gallium Arsenide (InGaAs)

Indium Arsenide (InAs)

Indium Antimonide (InSb

Cadmium Mercury Telluride (CMT/MCT)

Photoconductive detectors include:

Lead Sulphide (PbS)

Lead Selenide (PbSe)

Indium Antimonide (InSb)

Cadmium Mercury Telluride (CMT/MCT)

Detectors are mounted on transistor headers (TO-18, TO-5, TO-8, TO-3, etc) with optional thermoelectric cooling. Custom mountings are also available.

 

 

 

 

 

 

 

 

 

Matched preamplifiers for both photovoltaic and photoconductive detectors are available;

optimised for DC transconductive operation, best signal-to-noise or wide bandwidth.

 Detector Specification

Parameter

Ge

InGaAs

InAs

InSb

CMT

PbS

PbSe

Condition

Peak Responsivity (R)

(Typ) (A/W)

 

 

0.6-0.75

 

 

1.0

1.0

1.0

0.7

1.3-2.0

2.0-3.0

>1.0 V/W

>0.9 V/W

 

 

3x105 V/W

 

 

6,000 V/W

77 K

245 K

295 K

Shunt Resistance (R) (Typ) MW

(area dependent)

0.1

0.03

0.01

1.0

0.5

0.1

0.5

500 W

15 W

0.01

250 W

 

50 W

 

0.5-10

0.2-2.0

 

0.2-10

0.1-4.0

77 K

245 K

295 K

Capacitance (C)

(Typ) (pf)

@ 0V bias

(area dependent)

 

 

 300

 

 

50

100

10

8

-

-

77 K

245 K

295 K

Dark Current (Id)

(Typ) nA

@ 0V bias

(area dependent)

 

 

1-2

 

 

0.025

0.01

100

0.025

 

 

77 K

245 K

295 K

Recommended Cooling

 

*

*

*

*

*

*

*

*

*

*

*

 

*

*

 

*

*

-LN2 77 K

-TE 245 K

295 K

Recommended Preamplifier

MPA-2J

MPA-2J

MPA-2J

MPA-2J

MPA-3

MPA-2B

MPA-8

MPA-6

MPA-6

 

Encapsulation / Housing

KR204

TO8

TO-18/5/8

KR204

TO8

TO-18/5/8

KR204

TO8

TO-18/5/8

KR204

TO8

TO-18/5/8

KR204

TO8

TO-18/5/8

KR204

TO8

TO-18/5/8

KR204

TO8

TO-18/5/8

77 K

245 K

295 K

Window Material

(Standard)

BSC glass or quartz

BSC glass or quartz

Quarts or sapphire

Sapphire or Calcium Fluoride

Sapphire or Ge orZnSe

BSC glass

Sapphire or Calcium Fluoride

 

Above specifications are for a detector with an active area of 1mm diameter or 1mmx1mm

Note: shunt resistance, capacitance and dark current for photovoltaic detectors are area dependent. Smaller detectors have lower junction capacitance and faster speed of response.

 Detectivity / Spectral Response

InGaAs / Ge

 

 InAS / InSb

CdHgTe

 

  PbS

 

 PbSe

 

 

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