144
5 Optical Measurement Techniques
Fig. 5.8 Time-integrated and time-resolved spectroscopy in an optical microscopy setup typically
used for micro-PL measurements. a The pump light from a laser system is coupled into the setup
and focused onto the sample inside an optical cryostat through a microscope objective (e.g., with
20x magnification and NA 0.4, resulting in an excitation spot-size of about 4 µm). The collected
signal through the same objective is then directed towards diagnostics. On the optical axis, spatial
selection of the detection area can be achieved by an iris aperture in the sample projection plane. b
By employing a (flexibly removable) lens and flip mirror in the detection path, a CMOS camera can
be used to image the sample (also see Fig. 5.3). c If the light is focused onto the spectrometer slit,
time-integrated PL spectra can be acquired with the monochromator’s CCD (e.g., a nitrogen-cooled
Si CCD or Peltier-cooled iCCD). If an imaging monochromator is used, 1D-spatially-resolved
spectroscopy is enabled. d For dynamics studies such as lifetime measurements on different time
scales, either a gated detector (e.g., iCCD), an APD or a streak camera can be used to obtain timeresolved PL for rather long (ns–μs), intermediate (ps–ns) or short (ps) times, respectively, based
on the devices’ temporal resolution (common ranges indicated in parentheses). Note that the APD
can be similarly placed behind a monochromator, if not placed behind other appropriate spectral
filters. e In addition, angle-resolved spectroscopy is shown, which gives direct access to the Fourierspace (phase-space/far-field) plane and enables single-shot acquisition of far-field spectra with an
imaging spectrometer. Due to a microcryostat setup, measurements can be performed both at room
temperature and at cryogenic temperatures down to a few Kelvins or shortly below 100 K with
liquid helium or nitrogen, respectively. Drawn in a similar fashion as the author’s diagram used in
[5] and amended according to representations of the Fourier-space spectroscopy technique after [4,
14]
5 Optical Measurement Techniques
Fig. 5.8 Time-integrated and time-resolved spectroscopy in an optical microscopy setup typically
used for micro-PL measurements. a The pump light from a laser system is coupled into the setup
and focused onto the sample inside an optical cryostat through a microscope objective (e.g., with
20x magnification and NA 0.4, resulting in an excitation spot-size of about 4 µm). The collected
signal through the same objective is then directed towards diagnostics. On the optical axis, spatial
selection of the detection area can be achieved by an iris aperture in the sample projection plane. b
By employing a (flexibly removable) lens and flip mirror in the detection path, a CMOS camera can
be used to image the sample (also see Fig. 5.3). c If the light is focused onto the spectrometer slit,
time-integrated PL spectra can be acquired with the monochromator’s CCD (e.g., a nitrogen-cooled
Si CCD or Peltier-cooled iCCD). If an imaging monochromator is used, 1D-spatially-resolved
spectroscopy is enabled. d For dynamics studies such as lifetime measurements on different time
scales, either a gated detector (e.g., iCCD), an APD or a streak camera can be used to obtain timeresolved PL for rather long (ns–μs), intermediate (ps–ns) or short (ps) times, respectively, based
on the devices’ temporal resolution (common ranges indicated in parentheses). Note that the APD
can be similarly placed behind a monochromator, if not placed behind other appropriate spectral
filters. e In addition, angle-resolved spectroscopy is shown, which gives direct access to the Fourierspace (phase-space/far-field) plane and enables single-shot acquisition of far-field spectra with an
imaging spectrometer. Due to a microcryostat setup, measurements can be performed both at room
temperature and at cryogenic temperatures down to a few Kelvins or shortly below 100 K with
liquid helium or nitrogen, respectively. Drawn in a similar fashion as the author’s diagram used in
[5] and amended according to representations of the Fourier-space spectroscopy technique after [4,
14]