1. Overview of principal low light camera technologies

In this section we will limit ourselves to consideration of Electron Multiplying CCD (EMCCD), CCD, Intensified CCD (ICCD) and Electron Bombardment CCD (EBCCD) technologies.

Detector Type Advantages Disadvantages

EMCCD
  • Single Photon Sensitive
  • High and broad QE
  • Good resolution - Pixel limited
  • Good dynamic range possible
  • Fast or slow readout
  • Flexible - Operate as EMCCD or CCD (gain can be turned off). Conventional CCD amplifier on some sensors
  • No photocathode!
  • Relatively affordable (broad range of pricing, largely sensor dependent)
  • No nano or picosecond gating (microsecond gating available on some recent interline EMCCD sensors)
  • Multiplication noise (effectively increases shot noise by x1.41)

CCD
  • High and broad QE
  • Good resolution – pixel limited
  • Good dynamic range possible
  • No multiplication noise
  • No photocathode!
  • Greater choice of sensor formats available
  • Read noise limited - not single photon sensitive
  • Limited readout speed due to read noise restraints

ICCD
  • Single Photon Sensitive
  • Nano and Picosecond time-resolved gating possible
  • Fast or slow readout
  • NIR photocathode options
  • QE restricted by photocathode (<50% max)
  • Poor dynamic range – need to operate at high gains
  • Cross-talk between channels of MCP – increased point spread function
  • Higher multiplication noise
  • Artefacts, e.g. halo, chickenwire
  • Inflexible – no ‘CCD mode’
  • Expensive
  • Damage susceptible – longevity issues

EBCCD
  • Single Photon Sensitive (but not useful for SPC)
  • Minimal multiplication noise
  • Better resolution than ICCDs
  • NIR photocathode options
  • QE restricted by photocathode (<50% max)
  • Very poor dynamic range
  • High spurious noise from secondary electrons
  • Photocathode artefacts
  • Inflexible – no ‘CCD mode’
  • Expensive
  • Damage susceptible – longevity issues

Table 1 - Overview of principal camera technologies for low light measurement

2 What technology to use – rule of thumb guide