An interferometer system including: an optical system arranged to split a radiation beam from a laser source into a first beam along a first optical path and a second beam along a second optical path, and recombine the first beam and the second beam to a recombined beam, a detector to receive the recombined beam and to provide a detector signal based on the received recombined beam, and a processing unit, wherein a first optical path length of the first optical path and a second optical path length of the second optical path have an optical path length difference, and wherein the processing unit is arranged to determine a mode hop of the laser source on the basis of a phase shift in the detector signal.

An interferometer system including: an optical system arranged to split a radiation beam from a laser source into a first beam along a first optical path and a second beam along a second optical path, and recombine the first beam and the second beam to a recombined beam, a detector to receive the recombined beam and to provide a detector signal based on the received recombined beam, and a processing unit, wherein a first optical path length of the first optical path and a second optical path length of the second optical path have an optical path length difference, and wherein the processing unit is arranged to determine a mode hop of the laser source on the basis of a phase shift in the detector signal.

The invention discloses a method for measuring a complex degree of coherence of a random optical field by using a mutual intensity-intensity correlation, including the steps of: building a test optical path; rotating a quarter-wave plate to enable the fast axis of the quarter-wave plate to be consistent with a polarization direction of reference light, to obtain light intensity distribution information of a first combined light; rotating the quarter-wave plate to enable the slow axis of the quarter-wave plate to be consistent with the polarization direction of the reference light, to obtain light intensity distribution information of a second combined light; blocking the reference light to obtain light intensity distribution information of to-be-tested light; blocking the to-be-tested light to obtain light intensity distribution information of the reference light; and calculating the amplitude and phase of a complex degree of coherence of the to-be-tested light.

The invention discloses a method for measuring a complex degree of coherence of a random optical field by using a mutual intensity-intensity correlation, including the steps of: building a test optical path; rotating a quarter-wave plate to enable the fast axis of the quarter-wave plate to be consistent with a polarization direction of reference light, to obtain light intensity distribution information of a first combined light; rotating the quarter-wave plate to enable the slow axis of the quarter-wave plate to be consistent with the polarization direction of the reference light, to obtain light intensity distribution information of a second combined light; blocking the reference light to obtain light intensity distribution information of to-be-tested light; blocking the to-be-tested light to obtain light intensity distribution information of the reference light; and calculating the amplitude and phase of a complex degree of coherence of the to-be-tested light.

A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks, without a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. The special masking system is (1) a unity mask together with one or more bipolar binary masks with elements equal to 1 and −1, or (2) a unity mask together with one or more phase masks, or (3) a unity mask together with one pair of masks or more than one pair of masks having binary amplitudes of 0's and 1's, in which the masks in the pair are complementary to each other with respect to amplitude, or (4) one or more pairs of complementary masks with binary amplitudes of 0's and 1's without a unity mask.

A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks, without a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. The special masking system is (1) a unity mask together with one or more bipolar binary masks with elements equal to 1 and −1, or (2) a unity mask together with one or more phase masks, or (3) a unity mask together with one pair of masks or more than one pair of masks having binary amplitudes of 0's and 1's, in which the masks in the pair are complementary to each other with respect to amplitude, or (4) one or more pairs of complementary masks with binary amplitudes of 0's and 1's without a unity mask.

The disclosure relates to multifunctional sensors for mobile applications, namely to a miniature optical sensor for remote micro- and macro-object detection and characterization. The disclosure makes it possible to reduce the size of the sensor, this provides for surface mount of the sensor in any microcircuit of a mobile device. The sensor is multifunctional, low-power, vibration-resistant. The sensor comprises at least one pair consisting of a radiation source and a corresponding radiation receiver, an optical circuit including a collimating element, a first optical element, a second optical element. The first optical element and the second optical element are interconnected by a common surface, the common surface being a semitransparent surface. The sensor may be used simultaneously as a microphone, a dust sensor, a lidar, and a photoplethysmogram (PPG) sensor.

The disclosure relates to multifunctional sensors for mobile applications, namely to a miniature optical sensor for remote micro- and macro-object detection and characterization. The disclosure makes it possible to reduce the size of the sensor, this provides for surface mount of the sensor in any microcircuit of a mobile device. The sensor is multifunctional, low-power, vibration-resistant. The sensor comprises at least one pair consisting of a radiation source and a corresponding radiation receiver, an optical circuit including a collimating element, a first optical element, a second optical element. The first optical element and the second optical element are interconnected by a common surface, the common surface being a semitransparent surface. The sensor may be used simultaneously as a microphone, a dust sensor, a lidar, and a photoplethysmogram (PPG) sensor.

A method for detecting an analyte includes providing a sensor that includes a plurality of coupled polaritonic structures having polaritonic resonances. A surface of at least one of the polaritonic structure in the sensor is functionalized by providing a receptor for binding the analyte to the surface. The sensor is operated at an exceptional point (EP). The presence of the analyte on the surface is identified when a degeneracy of resonant frequencies and linewidths is lifted and a splitting of the resonant frequencies and linewidths occurs.

A method for detecting an analyte includes providing a sensor that includes a plurality of coupled polaritonic structures having polaritonic resonances. A surface of at least one of the polaritonic structure in the sensor is functionalized by providing a receptor for binding the analyte to the surface. The sensor is operated at an exceptional point (EP). The presence of the analyte on the surface is identified when a degeneracy of resonant frequencies and linewidths is lifted and a splitting of the resonant frequencies and linewidths occurs.