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We’re excited about the recent launch of two new microspectrometers from OtO Photonics.


SilverBullet spectrometerThe Bullet series offers OEM customers the utility of compact size, the assurance of ruggedised design and consistently accurate performance.


Despite their compact size spectrometers in the Bullet series feature an extremely rigid optical bench ensuring a platform with excellent thermal, humidity, shock and vibration stability.


Two versions of the Bullet design are available – SilverBullet uses a CMOS sensor for operation from ultraviolet to near infrared (180-1100nm) whilst the InGaAs sensor in RedBullet gives near infrared performance from 900nm-1700nm.

All Bullet series spectrometers are based on 8051 microcontrollers which allow for short integration time, fast readout, highly accurate trigger timing and low power consumption.


Compact Size

AConventional vs Concave 2 500s with other of their spectrometers, OtO Photonics’s Bullet range brings the sensitivity and resolution advantages of the classic Czerny-Turner (C-T) cavity design but replace the conventional arrangement of separate collimator and focussing mirror with a single complex concave reflector. This allows for a much reduced form factor compared to C-T spectrometer.


The drawing to the right illustrates shows a comparison of a traditional C-T cavity spectrometer design and OtO’s Bullet-series.

As a result the overall device volume is just 36cm³ for the SilverBullet and 54cm3 for the RedBullet, including control boards and connectors.


Product ruggedisation is a result of strong opto-mechanical design and manufacture:

  • Anti-vibration and anti-shock product casing allow for consistently accurate use.
  • Excellent thermal and humidity stability.


Spectroscopy accuracy

There are a number of benefits of the accuracy the Bullet series provides. These include:


  • Low stray light performance.
  • Storage chips of up to 64MB provide a large onboard memory. Combined with precise and continuous exposure, they ensure there is no latency in spectral reading.



The compact size of the Bullet series makes them ideal for handheld instrumentation. Just some of applications include:


  • Industrial: Petrochemical, agricultural, food and semiconductor thin film analysis; LED, VCSEL and laser inspection; solar cell production; plastic sorting/recycling.
  • Life sciences: Biological sample testing (blood, virus, DNA); forensic analysis; pharmaceutical testing; Optical Coherence Tomography (OCT).



If none of the pre-configured grating, sensor, slit and wavelength combinations meets your needs, customised variants can be produced at no additional cost.


Technical support and software

AP Technologies together with product engineers at OtO are available to provide fast and accurate support when this is needed. This includes system integration advice.


Dedicated spectral measurement software, SpectraSmart with full Windows SDK along with example code, is complimentary to purchasers of OtO spectrometers.


Bullet Series Specifications

Model RedBullet SilverBullet
Sensor 128 pixel InGaAs 1024 pixel CMOS
Slit width 50 μm 25/50/100 μm
Resolution (FWHM)

15 nm

Slit width 50 μm

3~15 nm

depending on combination of slit width and grating

SNR 2000 (High gain)
6000 (Low gain)
Dark noise <14 (High gain)
<10 (Low gain)
Dynamic range 6250 (High gain)
7200 (Low gain)
Integration time 6μs ~ 24sec 17μs ~ 24sec
Dimensions (mm) 51.4 (L) x 36.4 (W) x 29 (H) 40 (L) x 36.3 (W) x 25.1 (H)



If you’re curious how a Bullet spectrometer might work for your instrumentation system design, contact Martin at AP Technologies