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US 2019/0171042 A1Published application
Dual transducer photoelastic modulator
AssigneeHinds Instruments, Inc.
InventorsJohn Freudenthal, Baoliang Wang
Life of this patent
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Abstract
An apparatus includes a photoelastic modulator (PEM) optical element including a first driving axis and a second driving axis arranged at a selected angle with respect to each other and perpendicular to an optical axis, wherein the first driving axis and the second driving axis extend respective predetermined non-equal lengths that correspond to respective predetermined non-equal natural first and second PEM frequencies f1 and f2. Methods of manufacture and operation are also disclosed.
Claims25
An apparatus, comprising:
- a photoelastic modulator (PEM) optical element including a first driving axis and a second driving axis arranged at a selected angle with respect to each other and perpendicular to an optical axis, wherein the first driving axis and the second driving axis extend respective predetermined non-equal lengths that correspond to respective predetermined non-equal natural first and second PEM frequencies f1 and f2.
An apparatus, comprising:
- a dual-frequency photoelastic modulator (PEM) element including a pair of PEM driving axes situated at a predetermined angle with respect to each other and extending to predetermined respective non-equal lengths that correspond to predetermined non-equal natural frequencies;
- and
- a pair of transducers coupled to the PEM element so as to drive the PEM element along the respective driving axes at the respective non-equal natural frequencies.
A method, comprising:
- driving a first axis of a plurality of driving axes of a photoelastic modulator (PEM) element at a first natural frequency associated with the first axis, wherein the plurality of driving axes are situated at predetermined angles with respect to each other and extend predetermined respective non-equal lengths that correspond to predetermined non-equal natural frequencies;
- and
- detecting a beam modulated by the PEM element driven along the first axis.
A method, comprising:
- selecting non-equal driving axis lengths for a photoelastic modulator (PEM) optical element based on predetermined first and second PEM frequencies f1 and f2;
- and
- forming a singular PEM optical element having the selected non-equal driving axis lengths arranged at a selected angle with respect to each other so that the PEM optical element has the respective non-equal natural first and second PEM frequencies f1 and f2 associated with the respective lengths.
Dependencies are inferred from the claim text.