Kent Optronics
binned switchable notch filter

The B-NF series is an optically binned switchable notch filter made from Kent Optronics fast speed liquid crystal materials.

Data Sheet


The B-NF series is an optically binned switchable notch filter made from Kent Optronics' fast speed liquid crystal materials. Each B-NF filter consists of ≥2 filter bins to cover a broad spectral region (e.g., > 100 nm from the visible to infrared) for light blocking or routing. Each individual filter bin has a customized notch bandwidth. The filter can be rapidly switched between the transparent and reflection states.

The product series offers customers with an E-O component for purpose as an agile laser beam director, laser blocker, beam splitter, etc..., in the envisioned photonics systems, such as laser protection devices, remote sensing, vision-aid devices, and broadband light routing.

As compared to the state-of-the-art tunable notch filters containing passive polarizers, the B-NF series offers the following un-matchable performance specifications:

  • 2X lower insertion loss in transparent state
  • high optical density (OD) at the notch wavelength
  • >80% out band transmittance
  • ≤20 ms switching speed

The product comes with a compact power supply that can be either battery or 110/220 V wall-plug powered. Customers have the options to choose the filter substrate material, shape, aperture and the operation mode (i.e., manual or computer controlled). All products are offered at a competitive price. Contact us for a price quote with your specific application requirements.

The following is an exemplary 3-binned B-NF filter in the near IR.

sensor jammed by two lasers sensor recovered

3-bin NIR spectrum

3-bin contrast ratio

All 3 Bins are in Reflection State

Contrast Ratio

3-bin filter status #1

3-bin filter status #2

3-bin filter status #3

Short and Middle Bins are in
Reflection State

Short and Long Bins are in
Reflection State

Only Short Bin is in
Reflection State

B-NF™ Specifications

Spectral region 0.4-2.7 µm
Transmittance (blocking inactive) ~80%
Scene spectral neutrality (blocking inactive) Neutral
Polarizing properties Polarization insensitive
Tunable narrowband blocking waveband >300 nm (continuously tunable blocking)
Tunable narrowband blocking optical density OD>3 over the bandwidth
Angular range for broadband transmission (parallel light operation) >25° in air
Angular range for tunable narrowband blocking (parallel light operation) >25° in air
Clear aperture Diameter: 5-50 mm (circular)
Area: 5x5 to 50x50 mm² (square)
Thickness <10 mm
Operating temperature range -5°C (23°F) to 55°C (131°F) without heating mechanism;
-40°C (-40°F) to 55°C (131°F) with heating mechanism
Survival temperature range -51°C (-59.8°F) to 120°C (248°F)
Laser damage threshold >1 J/cm² (5ns pulsed @ 532nm)
>1 kW/cm² (CW @ 532nm)
Uniformity of retardance <0.1 OD across the clear aperture
Wavefront distortion <0.5 wavelength at 633nm
Parallelism <2 arcminutes
Response time 5.3 ms switching to blocking mode
Rate of change of temperature Survives a rate of change of temperature of 3°C per minute
Driving voltage Polarizer: 280V RMS
Retarder: 0-1.5V RMS
Computer interface USB interface w/PC
Weight <100g (filter only)
Substrate material Glass, quartz, and plastic (PC)
Cable length 1 m
Input power to the driver 110V or 220V/50-60 Hz AC or 9V battery
Total power consumption <4W
Power supply weight 200g