초록 ▼

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

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.

대표청구항 ▼

1. A method for providing a light beam having a sequence of two or more selected frequencies, the method comprising:providing an optical cavity, defined by at least first and second spaced apart mirrors, where the first mirror is movable relative to the second mirror to provide at least a first cavi

1. A method for providing a light beam having a sequence of two or more selected frequencies, the method comprising:providing an optical cavity, defined by at least first and second spaced apart mirrors, where the first mirror is movable relative to the second mirror to provide at least a first cavity configuration and a second cavity configuration corresponding to a selected first cavity frequency and a selected second cavity frequency, respectively; introducing a light beam, having a selected narrow frequency band, into the optical cavity arranged in the first cavity configuration and varying a distance of the first mirror from the second mirror, to produce a first light beam having the first cavity frequency; introducing the light beam into the optical cavity arranged in the second cavity configuration and varying a distance of the first mirror from the second mirror, to produce a second light beam having the second cavity frequency; positioning a sample of selected material within a selected portion of the cavity; sequentially allowing the first light beam and the second light beam to pass through the sample; sequentially extracting the first light beam and the second light beam from the cavity, after the first light beam and the second light beam have passed through the sample; analyzing said extracted first light beam and the extracted second light beam to determine absorption of the light beam at the first cavity frequency and at the second cavity frequency by the sample; choosing the sample absorption so that substantially all of at least one of the first light beam and the second light beam is extracted from the cavity within a selected time interval; and choosing round trip fractional sample absorption loss, .alpha.?d, and round trip fractional optical loss, .beta., in the cavity to approximately satisfy a relation (.tau.e-.DELTA..tau.-.DELTA..tau.0)?exp(-.beta.-.alpha.?d)=.tau.e-.DELTA..tau.0, where .DELTA..tau. is an estimated time interval for light beam round trip in the cavity, .DELTA..tau.0 is a selected fraction of .DELTA..tau. and .tau.e is the selected time interval for extraction of the light beam from the cavity.