Compare Model Drawings, CAD & Specs Wavelength Range Maximum Conversion Gain Responsivity CW Saturation Power Availability Price
190-1050 nm 102 to 106 V/W 0.5 A/W 30 mW per channel
900-1700 nm 2x102 to 2x106 V/W 1 A/W 15 mW per channel


  • Sensor Size
    2901: 3 x 3 mm
    2903: Ø3 mm
  • Transimpedance Gain
    2x102 to 2x106 V/A
  • Optical Input
    Free Space
  • Analog Output
    X, Y, SUM
  • Analog Output Voltage Range
    X & Y: ±2.5 V
    SUM: 0 to +2.5 V
  • Connector, Analog Output
    Male BNC
  • Analog Output Impediance
    1 kΩ
  • Power Requirements
    ±15 V, 50 mA power supply or 9V Battery
  • Bandwidth (-3 dB)
    100 kHz (30 Hz for SUM)
  • Detector Material
    2901: Silicon
    2903: InGaAs
  • Rise Time
    4 µs


Silicon or InGaAs Sensors

Model 2901 offers silicon sensors which are responsive in the 190-1050 nm wavelength range. Model 2903 uses InGaAs sensors for 900-1700 nm responsivity.

Highly Sensitive Beam Position Measurement

Quadrant-cell photoreceivers consist of four individual yet identical photocells positioned very close to each other (100-µm gaps). To increase the sensitivity of these photoreceivers, each of the cells’ photocurrents is sent to its own individual amplifier before being processed with the other photocell signals to generate top-minus-bottom difference (vertical error) and right-minus-left difference (horizontal error) signals. A sum-of-all-quadrants signal is also provided for normalization purposes.

Battery Operated or External DC Supply

The 2901 and 2903 quadrant-cell photo-receivers can run off batteries or your own DC power supply. To ensure low noise operation, we strongly recommend our Model 0901 power supply.

Using Optical Filters

Bandpass and neutral-density filters for filtering out unwanted light or attenuating the beam can be attached to the front of these photoreceivers with the aid of Newport's 1280 filter holder accessory (sold separately).


  • Shared-beam experiments
  • Beam stabilization
  • Semiconductor capital equipment
  • Defense and aerospace
  • Life sciences