Wheaton College Norton, Massachusetts
Wheaton College
Laser Lab

Facilities

In the Laser Spectroscopy Laboratory, we conduct experiments on optical properties of solids, including rare earth ion and transition metal ion-doped insulators and wide band gap semiconductors. Our capabilities include the following measurements:

Absorption, Transmission, and Reflection Measurements:

For these measurements we use a Perkin Elmer Lambda 750   UV/VIS/NIR Spectrophotometer, which can measure absorption and transmission between 190 and 3300 nm. With the reflection attachment (with 60 mm integrating sphere and InGaAs detector) we are able to measure diffuse reflectivity between 220 nm and 2500 nm.

Continuous and Time-Resolved Luminescence, Excitation Measurements, and Lifetime Measurements:

In a typical emission (luminescence) measurement, one obtains a spectrum showing the wavelength dependence of the intensity of the luminescence from our samples as a function of wavelength in the spectral region between 200 and 2000 nm.  In an excitation measurement, one obtains a spectrum of the intensity of the emission at a single wavelength as a function of the wavelength of light exciting the sample. In lifetime measurements, we measure the time dependence of the intensity of the emission from the sample following excitation with a pulsed laser.

The major pieces of equipment include:

Light sources:

  • Quantel TDL Laser: This is a Nd-YAG-pumped dye laser with frequency doubling, tripling, and mixing capabilities that allow us to generate 5 ns laser pulses at wavelengths between 200 and 900 nm.
  • Kimmon IK Series He-Cd Laser that produces 15 mW of CW power at 325 nm.
  • Hamamatsu Deuterium/Halogen lamp (model L10290).
  • ILC Technology 300 Watt Xenon Lamp

Dispersion of light:

  • A 0.5 meter Acton SpectraPro 500 Monochromator with resolution of 0.1 nm
  • A Jarrell-Ash 0.25 meter Monochromator

Detection of light:

  • Hamamatsu R-928 photomultiplier tube (200 – 850 nm)
  • Hamamatsu 7459 Photomultiplier tube  (190 – 600 nm), mounted in a Model TE327RF Products for Research TE-cooled housing.
  • Hamamatsu TE-cooled InGaAs infrared detector, an amplifier unit (model C1459-03), and a Temperature Controller (model C1103-04).

Other equipment:

  • The following items allow us to vary the sample temperatures from 7K to 300K: Cryo Industries Refrigerator (model REF-2302-204), Sunimoto HC-4A Compressor, and Lake Shore Cryogenics model 335 Temperature Controller.
  • Tektronix Digital Phosphor Oscilloscope, model 4104B (1 GHz bandwidth)
  • Quantum Composers Model 9520 Digital delay pulse generator
  • Newport Model ST 4’ x 10’ Optical Table
  • Various optical components (lenses, mirror, filters, etc.), holders, translation stages, etc.

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