CCD Primer

Bracket Pulsing
CCD Grading
Cosmic Rays
Dark Current
Deep Depletion CCD
Detection Modes
Dual Capacity Mode
Dual Readout Mode
Dynamic Range
Etaloning in CCDs
UV Extension
Fiber Optics
Flat Fielding
Full Well Capacity
Image Calibration
Imager Architectures
Image Intensifiers
Kinetics Mode
Matching Resolution
MPP Mode
Noise Sources
On-chip Multiplication Gain
Open Poly CCD
Optical Window
Quantum Efficiency
Readout vs Frame Rate
Reducing Dark Current
Saturation/ Blooming
Signal to Noise Ratio
Spurious Charge
XP Cooling


Deep Depletion CCD

NIR detection with regular CCDs can be quite challenging, especially for low-light applications, for the following reasons

  • 1. The silicon materials that CCDs are made becomes increasingly transparent in the NIR, which reduces the QE.
  • 2. Back-illuminated CCDs with high QE experience etaloning in the NIR range. The solution is the eXcelon CCD.
  • 3. Spectra and images taken in NIR suffer from thermal background noise in comparison to UV-VIS spectral range.

Deep Depletion CCDs (High-Resistance Silicon Substrate CCDs)
Deep depletion CCDs were specially designed for NIR applications which use a material called "epitaxial silicon,” comprised of high-resistance silicon with a highly doped substrate. Epitaxial silicon minimizes the distance in which the charge generated by photons can diffuse without being counted as a signal. Princeton Instruments offers thermo-electric (TE) and liquid nitrogen (LN) cooled deep depletion detectors. Because Back-illuminated Deep depletion CCDs cannot be made with an MPP mode, they have a higher dark current. As a result, the half hour rule of thumb cannot be used. Instead, TE-cooled devices should be chosen if the typical exposure time expected for the application is below half a minute. An LN-cooled device should be chosen as an alternative. Princeton Instruments offers multiple spectroscopy and imaging detectors fabricated in deep depletion technology. They are based on PIXIS and SPEC-10 platforms and utilize 100*1340, 400*1340 , 256*1024 and 1024*1024 CCD formats. Current Back-illuminated Deep depleted CCDs, such as the PIXIS /400BR, offers up to 35% QE at 1000 nm, which is especially beneficial for such critical applications like NIR Raman spectroscopy.

Deep Depletion Technology

Conventional back-illuminated CCD and the NIR optimized deep depletion CCD

Advantages of Deep depletion CCDs:

  • Ability to probe materials and biological tissues at deeper depths
  • Easy discrimination of NIR fluorescence from the tissue auto-fluorescence
  • Increased availability of economical NIR illumination sources such as NIR lasers
  • Development of a new class of stable, NIR fluorescent probes
  • Increased interest in research areas such as Bose Einstein Condensate (BEC
  • Astronomical imaging (especially solar research) in NIR region
  • Absolute highest QE in the NIR
  • Tailored for etaloning elimination
  • Special NIR optimized antireflective coating
  • Specially treated back surface structure to further break up etaloning