Chun-Chen Yen

Bio: Chun-Chen Yen is an academic researcher. The author has contributed to research in topics: Polarization (waves) & Linear polarization. The author has an hindex of 1, co-authored 1 publications receiving 6 citations.

Optical polarization rotating technique for characterizing linear birefringence with full range

Abstract: A simple interferometric scheme is presented to characterize the 2-D distribution of linear birefringence with full-range capability. Since the interference images are obtained with respect to different orientations of a linearly polarized incident laser beam, the measurement speed can be improved once the orientation adjustment is achieved electronically. In addition, the measurement is independent of a nonuniform distribution of laser intensity, which is demonstrated experimentally and briefly explained theoretically. Furthermore, the measurement of residual linear birefringence distribution is also demonstrated successfully and verified by error analysis.

Birefringence measurement using a confocal setup with a pair of birefringent lenses

Abstract: A confocal microscopic setup with a pair of birefringent lenses having their crystal axes crossed is used to measure birefringence of thin samples. The method can be used to measure phase down to the order of /10. The fast and slow axes of the object also can be identified. The principle of the method along with the experimental setup is described. Some first-order experimental results are also presented.

Full-field and full-range sequential measurement of the slow axis angle and phase retardation of linear birefringent materials.

Abstract: A method is proposed for obtaining full-range sequential measurements of the slow axis angle and phase retardation of linear birefringent materials (LBMs) using a full-field heterodyne interferometer with a charge-coupled device (CCD) camera and an image processing algorithm based on a three-frame integrating-bucket method. The dynamic ranges of the principal axis and phase retardation measurements extend from 0° to 180° and from 0° to 360°, respectively. The proposed method not only enables full-range measurements of the slow axis angle to be obtained, but also allows a decision to be made as to whether the principal axis labeled by the manufacturer is the slow axis or the fast axis. The standard deviations of the slow axis angle and phase retardation measurements are found to be 0.14° and 0.27°, respectively. In addition, it is shown that the noises induced by environmental disturbances are reduced by elimination of the dc component of the output light intensity in the image processing algorithm. We also investigate the sensitivity of the measured error caused by the orientation of LBM.

Excess noise reduction by optical technique in amplitude-sensitive heterodyne interferometer for small differential phase detection

Abstract: An amplitude-sensitive technique associated with a heterodyne interferometer for detecting small differential phase is reported. The excess noise with the amplitude-sensitive technique is reduced by optical subtraction instead of electronic subtraction. The differential phase introduced by the orthogonally polarized laser beams is converted to the amplitudes of two heterodyne interferometric signals, which presents amplitude and phase quadrature simultaneously. Thus the excess noise power and quantum noise power are both differential phase dependent. The advantages of differential and additive operations by optical technique and the real time differential phase determination without phase lock in are demonstrated experimentally. The theoretical signal-to-noise ratio (SNR) and minimum detectable differential phase are derived, which takes quantum noise and excess noise into consideration. The experimental results demonstrated the resolutions of differential phase detection closes to 10−6 rad/√Hz (10−13 m/√Hz) level over 100 kHz bandwidth and at 10−8 rad/√Hz (10−15 m/√Hz) level over 125 MHz bandwidth, respectively, under 2.5 mW incident power.