Digital holography metrology system

A method for operating a digital holography metrology system, the method comprising:

• operating a heterodyne light source, comprising:
• operating a multiwavelength light source to provide at least a first wavelength laser beam at a first frequency and a second wavelength laser beam at a second frequency that is different than the first frequency;
• and
• operating an acousto-optic modulator to:
• receive the first wavelength laser beam and generate a corresponding first frequency shifted laser beam which is combined with the first wavelength laser beam as a first combined beam;
• and
• receive the second wavelength laser beam and generate a corresponding second frequency shifted laser beam which is combined with the second wavelength laser beam as a second combined beam,
• wherein an interferometric optical arrangement receives the combined beams from the heterodyne light source and utilizes the combined beams for providing an output for imaging a workpiece, wherein the output comprises at least:
• a first interference beam which is produced based on the first combined beam from the heterodyne light source;
• and
• a second interference beam which is produced based on the second combined beam from the heterodyne light source;
• and
• operating a sensor arrangement to receive the output from the interferometric optical arrangement, the sensor arrangement comprising at least first and second time of flight sensors and a first dichroic component, wherein the first dichroic component is configured to separate the first interference beam from the second interference beam for which the first interference beam is directed to be received by the first time of flight sensor and the second interference beam is directed to be received by the second time of flight sensor.

A sensor arrangement for use in a digital holography metrology system, wherein the digital holography metrology system comprises:

• a heterodyne light source, comprising:
• a multiwavelength light source for providing at least a first wavelength laser beam at a first frequency and a second wavelength laser beam at a second frequency that is different than the first frequency;
• an acousto-optic modulator which is configured to:
• receive the first wavelength laser beam and generate a corresponding first frequency shifted laser beam which is combined with the first wavelength laser beam as a first combined beam;
• and
• receive the second wavelength laser beam and generate a corresponding second frequency shifted laser beam which is combined with the second wavelength laser beam as a second combined beam;
• an interferometric optical arrangement which receives the combined beams from the heterodyne light source and utilizes the combined beams for providing an output for imaging a workpiece, wherein the output comprises at least:
• a first interference beam which is produced based on the first combined beam from the heterodyne light source;
• and
• a second interference beam which is produced based on the second combined beam from the heterodyne light source,
• the sensor arrangement comprising:
• a first time of flight sensor;
• a second time of flight sensor;
• and
• a first dichroic component,
• wherein the sensor arrangement receives the output from the interferometric optical arrangement, and the first dichroic component is configured to separate the first interference beam from the second interference beam for which the first interference beam is directed to be received by the first time of flight sensor and the second interference beam is directed to be received by the second time of flight sensor.