With an Olis® Hummingbird double monochromator outputting a homogeneous excitation beam of arbitrary bandwidth, one has high resolution, low stray light excitation. With a single grating monochromator on the excitation side, one obtains the maximum emission signal.
Our 150-watt xenon arc lamp in a specialized elliptical mirrored housing outputs the intensity of a typical 450-watt xenon arc. A high sensitivity photon counter or a high-speed photomultiplier tube is used for detection. Arbitrary amounts of signal averaging are possible with both detectors. The photon counter, with higher sensitivity, responds in 10 milliseconds to 2.5 second intervals; the photomultiplier tube provides for an uninterrupted stream of acquisition, the rate of which is limited only by the 20 MHz A/D card or user-supplied digital oscilloscope and available memory.
Spectral ranges captured by the detectors is 210-650 nm or 300-850 nm with the photon counter, approximately 200-800 nm with the photomultiplier tube, and to 2600 nm with available InGaAs detectors.
Olis® SpectralWorks™ software lets you scan the monochromators independently or in synchrony, so that scanning excitation, fixed wavelength excitation, scanning emission, fixed wavelength emission, and synchronous scanning of emission and excitation are supported.
These same components can be used for light scatter or luminescence measurements, as well as single or dual beam absorbance data. (Without the emission monochromator, the Olis® DM 245 is an Olis® DB 620.)
The standard sample compartment houses a single 1 cm² jacketed cell holder. Alternative cell holders include two, four, six, and ten position units, with water jacketed thermal regulation or Peltier electronic thermal regulation. Polarizers and shutters can be positioned anywhere in the optical train of the fluorimeter to support L-format, T-format, or variable retardance methods1 of anisotropy measurements.
1)See also our Digital Method For Collecting Polarization of Fluorescence and Anisotropy
1) DeSa, Richard. 2005. Device for Enabling Slow and Direct Measurement of Fluorescence Polarization. U.S. Patent 6,970,241 B1, filed August 24, 2004, and issued November 29, 2005