Optical generator and detector of stress pulses
AssigneeBw Brown University Research Foundation
InventorsJan Tauc, Humphrey J. Maris, Christian Thomsen
Life of this patent
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Abstract
An optical stress pulse generation and detection system for non-destructively measuring physical properties of a sample, which uses a pump beam having short duration radiation pulses having an intensity and at least one wavelength selected to non-destructively generate a stress pulse in a sample and directs the non-destructive pump beam to a surface of the sample to generate the stress pulse. The optical stress pulse generation and detection system also uses a probe radiation beam and guides the probe beam to a location at the sample to intercept the stress pulse. The change in optical constants induced by the stress pulse is detected by observing the probe beam after it intercepts the stress pulse.
Claims37
An optical stress pulse generation and detection system for non-destructively measuring physical properties of a sample, comprising:
- a radiation source for providing a pulsed pump beam having at least one short duration radiation pulse having a duration of 0.01 to 100 psec, and having an intensity and at least one wavelength selected to non-destructively generate a stress pulse in a sample;
- a radiation source for providing a probe beam;
- means for directing said pump beam to a surface of a sample to generate said stress pulse in said sample;
- means for guiding said probe beam to a location at said sample to intercept said stress pulse;
- and
- means for detecting a change in an optical parameter of said probe beam representative of the change in optical constants induced by said stress pulse in said sample.
A system for non-destructively measuring physical properties of a sample in which both generation and detection of stress pulses is accomplished optically, comprising:
- a radiation source for providing a pulsed source beam, each pulse having a duration of 0.01 to 100 psec;
- beam splitting means for directing a first portion of said source beam to form a pump beam having an intensity and at least one wavelength selected to non-destructively generate a stress pulse in said sample and directing a second portion to form a probe beam;
- means for directing said pump beam to a surface of said sample to generate said stress pulse in said sample;
- means for guiding said probe beam to a location at said sample to intercept said stress pulse;
- and
- means for detecting a change in an optical parameter of said probe beam representative of the change in optical constants induced by said stress pulse in said sample.
A method for optically and non-destructively generating and detecting the propagation of a stress pulse in a sample, comrpising:
- producing a pulsed pump beam including short duration radiation pulses having a duration of 0.01 to 100 psec, and having an intensity and at least one wavelength selected to non-destructively generate a stress pulse in a sample;
- producing a probe radiation beam;
- directing the pump beam to a surface of the sample to generate said stress pulse in the sample;
- guiding the probe beam to a location at the sample to intercept the stress pulse;
- and
- detecting the change in optical constants induced by the stress pulse in the sample by measuring the intensity of the probe beam after it intercepts the stress pulse.
A method for optically and non-destructively generating and detecting the propagation of a stress pulse in a sample, comprising:
- producing a pulsed source beam having short duration pulses of radiation having a duration of 0.01 to 100 psec;
- diverting a first portion of the source beam to form a pump beam having an intensity and at least one wavelength selected to non-destructively generate a stress pulse in a sample;
- diverting a second portion of the source beam to form a probe beam;
- directing the pump beam to a surface of the sample to generate the stress pulse in the sample;
- guiding the probe beam to a location at the sample to intercept the stress pulse;
- detecting the change in optical constants induced by the stress pulse in the sample by measuring the intensity of the probe beam after it intercepts the stress pulse.
Dependencies are inferred from the claim text.