spectral sensing and imaging

We sort light.

CPI’s innovations come from our experts in the fields of physical science, mathematics, optical engineering and information technology. Practical experience and scientific depth enable us to innovate rapidly and creatively to meet the challenges that our customers face in manufacturing, imaging and non-contact sensing processes in both commercial and scientific applications.

Acquired by CPI in 2016, CPI New England (formerly known as Scientific Solutions, Inc. or SSI) is responsible for CPI’s spectral sensing and imaging, building on the foundation that SSI established over their 20+ year history. CPI New England integrates innovative electro-optic technology into mechanically robust, low power consumption, frequency-agile systems for imaging, defense, telecommunication and scientific research applications. CPI New England specializes in the fabrication of both classic Air-Gap Fabry-Perot Interferometers and next-generation Liquid Crystal Fabry-Perot (LCFP) tunable optical filters. This team was also responsible for the flight optics for the SENSE mission.


Air-Gap Fabry-Perot Interferometer

CPI specializes in the construction of classic air-gap Fabry-Perot Interferometers (FPIs); our staff has over 40 years of collective FPI experience. These precision instruments yield maximum throughput for a given spectral resolution. Custom features include diameters from 1 cm to 6 inches and resonant cavity spacing from 3 μm to 6 cm.

  • Custom design and fabrication
  • Outer diameters from 1 cm to 6 inches
  • Resonant cavity spacing from 3 µm to 6 cm
  • Maximum throughput for a given spectral resolution
  • Operating ranges in the VIS, NIR, IR, MWIR, and LWIR
  • Optional pressure-pot
  • Optional temperature stabilization

Liquid Crystal Fabry-Perot Interferometer

These are high-resolution (Doppler) filters and low resolution (imaging) filters. The technology uses nematic liquid crystal as the tuning medium in Fabry-Perot interferometers. Proprietary NUV - LWIR designs.

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Diverse Applications
Spectroscopy, Imaging (Raman, Fluorescence, Non-excited, and Hyperspectral), Sensing, Astronomy/Astrophysics/Aeronomy, LIDAR, Telecommunications (WDM, Add-Drop, Spectrum Analysis, Channel Monitoring), Laser tuning

  • Precise electronic wavelength selection
  • Completely solid-state design
  • Remarkable ease of use
  • Extreme resistance to shock and vibration
  • Rapid tuning on the order of milliseconds
  • Low-voltage analog input (0-10V max)
  • Excellent background rejection
  • Remarkable image quality
  • Diameters from 10 to 152 mm
  • Wavelength regions from 500 nm to 14 µm
  • Spectral resolution from 0.002 to 36 Å (VIS)
  • Absolutely no closed-loop control
Download a paper on Liquid Crystal Tunable Filters

Lowell Doppler (Air-Gap) Interferometer

State of the art, observatory-class ground based system available at a modest cost.

  • Telecentric optical system, with objective lens diameter up to 150 mm
  • Andor iKon 1024 x 1024 scientific imaging camera
  • Two-mirror servo driven pointing system with stand-alone controller and web interface
  • ImageTool - data acquisition software
  • Remote laser calibration system
  • 19” rack mounted control systems and computer
  • Technical support for software, including remote login capability

Spatial Heterodyne Spectrometer

The Spatial Heterodyne Spectrometer (SHS) combines the high resolution and throughput of conventional interferometers with extreme robustness. The SHS does not require scanning to function at its full resolving power. The SHS can be made monolithic by fusing all of the main optical elements into a single block with no moving parts. CPI specializes in SHS with over 10 years of hands-on experience.

  • No mechanical, pressure, or voltage scanning required
  • Can be designed for any wavelength from 150 nm to 1.5 microns
  • Extremely robust
  • Spectral resolution as low as 0.001 nm in the visible
  • Size range continuous from < 5 mm to 100+ mm
  • Bandpass from a few nm to 100+ nm
  • Monolithic design available for increased robustness
  • Fourier transform spectrometer
  • Analysis software included

Imagers and Spectrographs

Walden Small All-Sky Imager

Small, all-sky fisheye spectral imager capable of imaging an entire 180-degree field of view simultaneously.

More information
Optically, the all-sky field of view is imaged onto a 1392 x 1040 pixel Sony CCD at F/0.95. A telecentric design ensures that all the chief rays are at normal incidence at the image plane, allowing the use of narrow bandpass interference filters (< 2nm) in the five-position filter wheel.

  • All-sky imaging
  • Auroral imaging and detection
  • Cloud monitoring
  • Astronomical extinction measurements
  • Meteor imaging and detection
  • Aerosol and pollution monitoring
  • Security and surveillance

  • Features
  • Mounting: vertical (as a mast)
  • Finish: anodized
  • Field of view: 180°
  • Camera: Atik 314L+ or Atik 414 Ex
  • CCD: Sony ICX285AL or Sony ICX825
  • 1392 x 1040 pixels
  • 6.45m x 6.45m pixels
  • Chip dimension: 8.9mm x 6.7mm
  • Peak QE: 65% (Atik 314L+) or 73% (Atik 414EX) at 540nm
  • Full well capacity: 19,500 e- (Atik 314L+) or 18,000 e- (Atik 414EX)
  • Dark current: 0.0002 e-/s at -10°C (Atik 314L+) or 0.001e-/s at -10°C (Atik 414EX)
  • USB 2 built-in computer interface download rate: 3.7s Full resolution
  • Computer included
  • Software: Maxim DL or ImageTool Control Software

Middlesex Imaging Spectrograph

The Middlesex Spectrograph is a compact, meridional instrument capable of imaging a full 180° slice of the sky onto the 1292 x 1040 pixel CCD. With a spectral resolution of 2nm or less, and a spectral range of 400 - 800nm, this spectrograph is ideal for auroral and airglow spectroscopy.

  • Spectral resolution: 2nm, or less, depending upon slit size
  • Field of view: 180° along slit
  • Spectral range: 400nm to 800nm
  • Photometric sensitivity: 4.6 photons/sec-pixel-kilorayleigh
  • Ex: 1 kilorayleigh auroral signal with 3x1 binning (perpendicular to slit) produces 13.8 photons/pixel in a 1 second integration period
  • A 30 rayleigh airglow signal binned 3x1 and using a 15 second integration generates 6 photons/pixel
  • Read noise 4e-
  • Robust, monolithic design
  • Software included
  • No mechanical, pressure, or voltage scanning


ImageTool Control Software

ImageTool is an integrated data acquisition and device configuration software for CPI New England's spectral sensing and imaging instruments. High-end scientific cameras such as Andor and ATIK cameras are supported, in addition to filter wheel controllers, temperature and pressure controllers and mirror systems. The software provides scheduling capabilities for automated data acquisition.

Field Instrumentation

Wamesit Space Weather Station

A turnkey housing unit for space weather instruments. The station has an optical dome and temperature-controlled interior. The housing operates on 110 volts and communication capabilities include 4G, LTE, and Wi-Fi. An onboard computer handles all data acquisition and the GPS is for TEC measurements in the ionosphere.