Anomalous vibration suppression in a weak-value-emulated heterodyne roll interferometer

Heterodyne interferometer with two parallel-polarized input beams for high-resolution roll angle measurement

“…We attribute this to the laser drift, air turbulence, instability of the phase meter, and the statistic limits which include the quantum noise (shot noise) and the detector noise. Since the severely attenuated intensity of the AC signal, the detector noise limits our results over the shot noise [17,23]. An ideal measurement resolution about 0.03/G = 0.47 arcsec is expected to be attained considering all the above factors.…”

“…To understand the drawback of the previous interferometers, the principles of the two structures are introduced here. For the scheme of single-pass in [17], the polarization states of the measurement light passing the optical plates are explained in detail as follows. The laser source contains two orthogonally polarized beams with frequency f 1 and f 2 .…”

“…That explains why θ was set as a small orientation in the measurement. However, it comes at the cost of severe intensity drop [17]. Therefore, the angle of the QWP θ cannot be too small.…”

“…Combined with a reference signal, the phase shift can be detected to calculate the roll error. Hong Jiang et al proposed a method adding a quarter wave plate (QWP) right after the emitted source [16,17]. The fast axis of QWP was set a small deviation angle of θ from the polarization state of the TM beam, which dramatically improved the measurement resolution.…”

“…The phase shift, as the output of the interferometer, is composed of the phase shifts of two beams with different frequencies. All of the sources used in previous heterodyne roll measurement interferometers were orthogonally polarized dual-frequency lasers provided by Zeeman split or modulated acousto-optic modulators (AOM) [16][17][18][19][20][21][22]. The phase shift of each mode shows a high sensitivity within a specific roll area, called the sensitive area, in which the roll error is converted to a detectable phase shift by the gain factor.…”