scholarly journals Laser Intensity Noise Suppression for Preparing Audio-Frequency Squeezed Vacuum State of Light

2020 ◽  
Vol 10 (4) ◽  
pp. 1415
Author(s):  
Lele Bai ◽  
Xin Wen ◽  
Yulin Yang ◽  
Jun He ◽  
Junmin Wang
Keyword(s):  
Laser Beam ◽  
Noise Suppression ◽  
Laser Intensity ◽  
Vacuum State ◽  
Intensity Noise ◽  
Audio Frequency ◽  
Uv Laser ◽  
Optical Modulators ◽  
Squeezed Vacuum State ◽  
Squeezed Vacuum

Laser intensity noise suppression has essential effects on preparation and characterization of the audio-frequency squeezed vacuum state of light based on a sub-threshold optical parametric oscillator (OPO). We have implemented two feedback loops by using relevant acousto-optical modulators (AOM) to stabilize the intensity of 795-nm near infrared (NIR) fundamental laser and 397.5-nm ultraviolet (UV) laser generated by cavity-enhanced frequency doubling. Typical peak-to-peak laser intensity fluctuation with a bandwidth of ~10 kHz in a half hour has been improved from ±7.45% to ±0.06% for 795-nm NIR laser beam, and from ±9.04% to ±0.05% for 397.5-nm UV laser beam, respectively. The squeezing level of the squeezed vacuum state at 795 nm prepared by the sub-threshold OPO with a PPKTP crystal has been improved from −3.3 to −4.0 dB around 3~9 kHz of analysis frequency range.

LEGENDRE POLYNOMIALS AS THE NORMALIZATION OF PHOTON-SUBTRACTED SQUEEZED STATES

2009 ◽  
Vol 24 (20) ◽  
pp. 1597-1603 ◽  
Author(s):  
HONG-YI FAN ◽  
LI-YUN HU ◽  
XUE-XIANG XU
Keyword(s):  
Legendre Polynomial ◽  
Legendre Polynomials ◽  
Hermite Polynomial ◽  
Vacuum State ◽  
Squeezed States ◽  
Squeezed State ◽  
Normalization Factor ◽  
Squeezed Vacuum State ◽  
Squeezed Vacuum ◽  
Excitation State

By converting the photon-subtracted squeezed state (PSSS) to a squeezed Hermite-polynomial excitation state we find that the normalization factor of PSSS is an m-order Legendre polynomial of the squeezing parameter, where m is the number of subtracted photons. Some new relations about the Legendre polynomials are obtained by this analysis. We also show that the PSSS can also be treated as a Hermite-polynomial excitation on squeezed vacuum state.

High Order Nonclassical Properties of the Squeezed Vacuum State

2019 ◽  
Vol 25 (3) ◽  
pp. 252-258
Author(s):  
范有机 FAN You-ji ◽  
卢道明 LU Dao-ming
Keyword(s):  
Vacuum State ◽  
High Order ◽  
Squeezed Vacuum State ◽  
Squeezed Vacuum ◽  
Nonclassical Properties

CORRELATION OF SUPERCURRENTS IN TWO DISTANT MESOSCOPIC SQUID RINGS IN THE PRESENCE OF TWO-MODE NONCLASSICAL FIELD

2005 ◽  
Vol 19 (11) ◽  
pp. 1965-1971 ◽  
Author(s):  
Z. H. PENG ◽  
J. ZOU ◽  
B. SHAO ◽  
J. F. CAI
Keyword(s):  
Quantum Interference ◽  
Vacuum State ◽  
Superconducting Quantum Interference Device ◽  
Squeezed Vacuum State ◽  
Squeezed Vacuum ◽  
Superconducting Quantum Interference ◽  
Squid Rings ◽  
Degree Of Entanglement

In this paper we consider two distant mesoscopic superconducting quantum interference device (SQUID) rings A and B in the presence of two-mode squeezed vacuum state field, and aim to see the effect of the field on the correlation of supercurrents in the two rings. We know the degree of entanglement of the two-mode squeezed vacuum state increases with the squeezing parameter r. In this paper we find that the correlation of the supercurrents increases with the parameter r too, meaning that the correlation of the supercurrents increases with the degree of entanglement of the field.

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