Wavenumber Standards for Mid-infrared Spectrometry

Bond-Selective Imaging of Cells by Mid-Infrared Photothermal Microscopy in High Wavenumber Region.

Using a visible beam to probe the thermal effect induced by infrared absorption, mid-infrared photothermal (MIP) microscopy allows bond-selective chemical imaging at submicron spatial resolution. Current MIP microscopes cannot reach the high wavenumber region due to the limited tunability of the existing quantum cascade laser source. We extend the spectral range of MIP microscopy by difference ...

Nira Symposium July 7-8, 1982

Although Near Infrared Analysis (NIRA) as a technique can be traced back to the late 19th century, the first commercial instrumentation (Cary 14) was made available in the mid 1950's. Significant growth in the number of NIRA instruments used did not occur until the 1978-1982 period. During this time, the number of units utilized has grown at an annual compounded growth rate of well over sixty p...

Fiber-optic Probes for Mid-infrared Spectrometry

The effective wavelength for broadband fringe detection using fringe scanning

The spectroscopic wavenumber is a proxy for the optical frequency, and avoids the necessity of writing factors of c everywhere. For optical and infrared radiation the wavenumber is conveniently expressed in units of inverse micrometers, thus a wavelength of 500 nm corresponds to 2.00 μm−1. The circular or angular wavenumber k = 2π/λ = 2πσ is often used, particularly in the context of the wave e...

Correcting nonlinear response of mercury cadmium telluride detectors in open path Fourier transform infrared spectrometry.

The effect of a nonlinear response of mercury cadmium telluride (MCT) detectors to photon flux is to cause a large offset and a slow variation in the zero-line of single-beam Fourier transform infrared (FT-IR) spectra, which dramatically reduce the accuracy to which strongly absorbing bands or lines can be measured. We describe a noniterative numerical technique by which the baseline offset can...