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Small Spectrometers, Big Performance: Solutions for System Integration

The Bullet Range of Spectrometers from AP Technologies

The Bullet Range of Spectrometers from AP Technologies

Systems developers seeking high performing compact spectrometers can rely on the new near-infrared (NIR) Bullet range from OTO Photonics.

OtO Photonics, has a twenty-year track record of developing market-leading spectroscopy solutions for industrial and life science applications.

Uncompromising accuracy meets unwavering durability: The Bullet series of compact, ruggedised spectrometers are ideal for a variety of OEM applications requiring exceptional data integrity.

Spectroscopy Accuracy

OtO has innovated several proprietary technologies that deliver comparable performance to traditional Czerny-Turner (C-T) cavity spectrometers without the compromises in accuracy or consistency that other commercially available microspectrometers incur as a result of miniaturisation. As a result, the Bullet range provides:

  • Onboard memory capacity extending up to 64MB with storage chips, offering ample storage. Coupled with accurate and uninterrupted exposure, this configuration guarantees no delays in spectral reading.
  • Stray light control standards comparable to larger spectrometers, of 0.2% or less, has been achieved by means of a proprietary black coating. OtO Black provides significantly superior reflectivity compared to other comparable commercially available alternatives. This remarkable achievement is attested by these performance graphs.


A comparison between OtO Black coating and coatings from other leading providers

Product Ruggedisation

Product performance in harsh environments is enabled by strong opto-mechanical design and manufacture:

  • Accuracy and consistency are ensured by anti-vibration and anti-shock features.
  • Demonstrably outstanding stability in thermal and humidity conditions.

Compact Form

OtO is globally recognized for its expertise in miniaturising high-resolution microspectrometer technology tailored for handheld and portable instrumentation. Collimator and focussing mirrors are combined into a single curved component resulting in reduced size and weight without comprising either sensitivity or resolution.

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A comparison of a traditional C-T cavity spectrometer design and OtO’s Bullet-series


Bullet Series

In 2023 OtO brought the Bullet range to market with the:

SilverBullet employs a linear CMOS sensor capable of operating from ultraviolet to near-infrared (180-1100nm), while RedBullet utilises a linear InGaAs sensor, providing near-infrared performance within the 900-1700nm range. Hamamatsu provide sensors for both models.

OtO are in the late stages of developing the GoldBullet, a thermoelectrically cooled version of the RedBullet. The GoldBullet will be the world’s smallest TE-cooled NIR spectrometer with proposed dimensions of: 97.5 x 110 x 70.

GoldBullet microspectrometer prototype


GoldBullet microspectrometer prototype

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.

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.


OTO spectrometers from AP Technologies can be used for a bewildering range of applications. Just some of these 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).

About AP Technologies

AP Technologies are a UK distributor of optoelectronic components with over 30 years’ experience supplying an exceptionally broad range of cutting-edge optoelectronic components and subsystems from leading and trusted suppliers around the world. We work with customers to recommend the best solution for each application and platform.

Contact AP Technologies

Get in touch for an informal discussion about your application needs and learn how APT can help. |+44 (0)1225 780400 |


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