Leland Stanford Junior University

Informed Diagnostics, Inc.

Informal Diagnostics, Inc

Charles C Harb

Richard Neil Zare

Barbara A Paldus

Thomas G Spence

Gerard Meijer

An analog detection system for determining a ring-down rate or decay rate 1/&tgr; of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

Analog detection for cavity lifetime spectroscopy

Method and system for cavity ring down spectroscopic analysis of non-cavity-filling sample. An interface of a sample (gas, liquid, thin film, bulk solid, etc.) is positioned at a Brewster angle relative to a p-wave polarized light beam propagating in an optical cavity so that substantially no light beam energy is lost by reflection at the interface. The light beam cycles one or more times in the cavity for each of a sequence of selected wavelengths, is extracted from the cavity, and is analyzed to determine an absorption spectrum for the sample. The cavity, except for the sample region may be filled with a solid, optionally dielectrically active and optionally having an electrical field applied thereto to vary the solid's refractive index according to the light beam wavelength used.

Cavity ring down arrangement for non-cavity filling samples

Method and system for generating a sequence of two or more light beam central frequencies. A first mirror, in an optical cavity defined by two or more mirrors, is moved to a sequence of two or more locations relative to a second mirror in the cavity. The first mirror location is dithered relative to the second mirror for each location in the sequence to produce a light beam having a dithered sequence of cavity frequencies that are related to longitudinal mode resonant frequencies for the cavity. Alternatively, frequency locking is implemented for each of the sequence of central frequencies. The light beam may be passed through a sample within the cavity for spectroscopic measurements or may be extracted from an empty cavity to provide a sequence of light beam frequencies for a subsequent application.

Frequency sequencing using CRDS

Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

Growing community of inventors

Palo Alto, CA, United States of America

Charles C Harb