Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of the Optical Society of America B

Significance of field and medium asymmetry for the generation of squeezed light

Harneet Kaur Gahir, Pratima Sen, Pranay K. Sen

Published May 1, 2003• 2 citations
Publisher

Abstract

The roles of the asymmetry of coherent light and of an active medium in squeezed-state generation in a weakly noncentrosymmetric semiconductor are discussed. It is suggested that origin of medium asymmetry lies in the parity indefiniteness of the transition states, whereas field asymmetry is due to the polarization property of light. Third-order nonlinear optical susceptibility is obtained from the semiclassical density matrix approach, whereas the light-squeezing process is studied by use of Heisenberg’s equation of motion. The analysis is applied to GaAs that has been duly irradiated by a tunable nanosecond pulsed Co:MgF2 laser with its photon energy off resonant below the semiconductor’s band edge. It has been found that the effect of asymmetry on squeezed-state generation and photon number is finite only when both of the asymmetries are present simultaneously. One may also notice that the asymmetry improves the squeezing level and reduces the time span of squeezed-light generation.

DOI
10.1364/josab.20.000871

Related papers

Squeezed Light Generation in Semiconductors

A. M. Fox, J.J. Baumberg, Maurizio Dabbicco +2 more

The signal to noise ratio of optical systems is ultimately limited by the shot noise due to the Poissonian statistics of the light field. In recent years there has been a considerable effort to find ways to overcome this limitation by generating non-classical light with sub-shot noise statistics. Several groups have demonstrated non-classical light generation in diode lasers or light emitting diodes, and the amplitude fluctuations have been reduced substantially below the shot noise level [1,2]. However, for phase-sensitive measurements it is necessary to generate the more general quadrature squeezed states. Such quadrature squeezed light can be generated either by second-order or third-order nonlinear processes provided the nonlinear material has very low losses at the optical wavelength. To date, the successful generation schemes for quadrature squeezed light have been restricted to atomic vapours, optical fibres, or second-order nonlinear crystals [3]. The possibility of using the large χ(3) nonlinearities of semiconductors at frequencies below the band gap where the optical absorption is small has been discussed in the literature, but so far there have been no successful experiments [4-6]. In this paper we report measurements on GaAs/Al0.3Ga0.7As multiple quantum well waveguides and bulk ZnS in the wavelength range 750 - 890nm. Although we measure much larger nonlinearities in the quantum wells, the strong two-photon absorption is detrimental for squeezed light generation. However, in the ZnS where the laser frequency is below the two- photon absorption edge, we have succeeded in generating quadrature squeezed light in a semiconductor for the first time. On the basis of our results, we would expect that squeezed light could be generated in many other semiconductor systems provided the photon energy is less than half the band-gap energy.

Quantum Optoelectronics•Jan 1, 1995•13 citations

Squeezing Property of Coherent Light Coupled to a Nonlinear Medium of Inversion Symmetry

Hong Li

An analytical approach is adopted for the calculation of squeezed property of coherent light interacting with a nonlinear medium of inversion symmetry. A medium is called inversion symmetric if the potential energy remains invariant under parity transformation. Thus the even order susceptibilities would vanish for the medium and the leading contribution to the nolinear polarization due to the medium is the third order susceptibility. Therefore interaction Hamitonian of the single mode light field with the medium is proportional to the fourth power of the annihilation operator plus creation operator. This means is to take care all the non conserving energy terms for the calculation of the squeezing property of coherent light passing through the nonlinear medium of inversion symmetry. For a single mode light, two dimensionless quadrature operators are defined which are proportional to the usual position and momentum operators respectively. Using the Heisenberg operator equation of motion, the differential equation of the quadrature operators and the approximate solutions to the equations are got. Then the quantum fluctuations of the two quadratures are calculated. The result shows that the squeezing property of the two quadrature operators is controllable through changing the following parameters: coupling constant, mean photon number, light field frequency, and interaction time.

Chinese Journal of Lasers•Jan 1, 2004•0 citations

Squeezed light generation in semiconductors

J.J. Baumberg, A. M. Fox, M. Dabbiccco +2 more

We have generated pulsed squeezed light using the third-order nonlinear susceptibility of the semiconductor ZnS at room temperature. The photon energy was chosen to be below midgap in order to minimize nonlinear absorption. Efficient quadrature squeezing of 2.2 dB (40%) was obtained using 125 fs pulses at a center wavelength of 780 nm. The measured noise is suppressed below the quantum limit over the entire range of our detection bandwidth (30–50 MHz). The scheme employed can generally be applied to semiconductors, and opens the way for squeezed light generation over a wide range of wavelengths.

•Aug 24, 2005•23 citations

Squeezed Light Generation in Semiconductors

A. M. Fox, J.J. Baumberg, Maurizio Dabbicco +2 more

We have generated pulsed squeezed light using the third-order nonlinear susceptibility of the semiconductor ZnS at room temperature. The photon energy was chosen to be below midgap in order to minimize nonlinear absorption. Efficient quadrature squeezing of 2.2 dB (40%) was obtained using 125 fs pulses at a center wavelength of 780 nm. The measured noise is suppressed below the quantum limit over the entire range of our detection bandwidth (30-50 MHz). The scheme employed can generally be applied to semiconductors, and opens the way for squeezed light generation over a wide range of wavelengths.

Physical Review Letters•Mar 6, 1995•81 citations

Squeezed light generation in a monomode optical fiber

Mary J. Potasek, Bernard Yurke

Squeezed light, in which the quantum noise in one amplitude component is reduced below the vacuum level, has been generated using parametric processes. The starting point described here is the nonlinear Schrodinger equation which models light propagating through optical fibers. When such a dispersive nonlinear medium with a third-order susceptibility is pumped with an optical beam, squeezing can result. It is found that the degree of squeezing oscillates as a function of fiber length in the normal dispersion regime, whereas in the anomalous dispersion regime, it grows exponentially with fiber length. Examination of squeezing near the fiber’s zero dispersion wavelength shows that odd-order dispersive terms have no effect on squeezing. However, small values of higher-order even terms have significant effects on squeezing. In practice, high-frequency components of the squeezing spectrum are difficult to obtain. However, it is shown that a cross-correlation technique may be used to explore the frequency dependence of the squeezing spectrum.

Annual Meeting Optical Society of America•Jan 1, 1987•0 citations

Photon-number squeezed light generated by semiconductor lasers: Applications and quantum noise processes.

Daniel C. Kilper

In this dissertation measurements are presented that extend our understanding of the important noise processes involved in the semiconductor laser generation of photon-number squeezed light. Strong sub-shot noise correlations between photon-number fluctuations on orthogonal polarization axes are observed in the output of a low temperature injection-locked quantum-well laser. Such polarization dependent effects are accounted for by intrinsic correlations generated in the laser gain medium and polarization mixing due to birefringence. Using polarization preserving balanced homodyne detection, up to 4.5 dB of photon-number squeezing is reported, which is within 95% of the expected maximum squeezing based on the device quantum efficiency. The work in this dissertation demonstrates the application of such nonclassical fields to practical measurements that achieve sub-shot noise sensitivity. Coherent nonlinear optical spectroscopy with a photon-number squeezed probe field is used to measure the Urbach tail and exciton resonances in a GaAs/AlGaAs multiple quantum well with sensitivity below the semiclassical shot-noise limit. Direct drive current modulation of an injection-locked room temperature laser results in a nonclassical amplitude modulated field with a signal to noise ratio that exceeds the maximum ratio permitted for a classical source under equivalent modulation conditions.

•Jan 1, 1996•0 citations
The roles of the asymmetry of coherent light and of an active medium in squeezed-state generation in a weakly noncentrosymmetric semiconductor are discussed. It is suggested that origin of medium asymmetry lies in the parity indefiniteness of the transition states, whereas field asymmetry is due to the polarization property of light. Third-order nonlinear optical susceptibility is obtained from the semiclassical density matrix approach, whereas the light-squeezing process is studied by use of Heisenberg’s equation of motion. The analysis is applied to GaAs that has been duly irradiated by a tunable nanosecond pulsed Co:MgF2 laser with its photon energy off resonant below the semiconductor’s band edge. It has been found that the effect of asymmetry on squeezed-state generation and photon number is finite only when both of the asymmetries are present simultaneously. One may also notice that the asymmetry improves the squeezing level and reduces the time span of squeezed-light generation.
The signal to noise ratio of optical systems is ultimately limited by the shot noise due to the Poissonian statistics of the light field. In recent years there has been a considerable effort to find ways to overcome this limitation by generating non-classical light with sub-shot noise statistics. Several groups have demonstrated non-classical light generation in diode lasers or light emitting diodes, and the amplitude fluctuations have been reduced substantially below the shot noise level [1,2]. However, for phase-sensitive measurements it is necessary to generate the more general quadrature squeezed states. Such quadrature squeezed light can be generated either by second-order or third-order nonlinear processes provided the nonlinear material has very low losses at the optical wavelength. To date, the successful generation schemes for quadrature squeezed light have been restricted to atomic vapours, optical fibres, or second-order nonlinear crystals [3]. The possibility of using the large χ(3) nonlinearities of semiconductors at frequencies below the band gap where the optical absorption is small has been discussed in the literature, but so far there have been no successful experiments [4-6]. In this paper we report measurements on GaAs/Al0.3Ga0.7As multiple quantum well waveguides and bulk ZnS in the wavelength range 750 - 890nm. Although we measure much larger nonlinearities in the quantum wells, the strong two-photon absorption is detrimental for squeezed light generation. However, in the ZnS where the laser frequency is below the two- photon absorption edge, we have succeeded in generating quadrature squeezed light in a semiconductor for the first time. On the basis of our results, we would expect that squeezed light could be generated in many other semiconductor systems provided the photon energy is less than half the band-gap energy.
An analytical approach is adopted for the calculation of squeezed property of coherent light interacting with a nonlinear medium of inversion symmetry. A medium is called inversion symmetric if the potential energy remains invariant under parity transformation. Thus the even order susceptibilities would vanish for the medium and the leading contribution to the nolinear polarization due to the medium is the third order susceptibility. Therefore interaction Hamitonian of the single mode light field with the medium is proportional to the fourth power of the annihilation operator plus creation operator. This means is to take care all the non conserving energy terms for the calculation of the squeezing property of coherent light passing through the nonlinear medium of inversion symmetry. For a single mode light, two dimensionless quadrature operators are defined which are proportional to the usual position and momentum operators respectively. Using the Heisenberg operator equation of motion, the differential equation of the quadrature operators and the approximate solutions to the equations are got. Then the quantum fluctuations of the two quadratures are calculated. The result shows that the squeezing property of the two quadrature operators is controllable through changing the following parameters: coupling constant, mean photon number, light field frequency, and interaction time.
We have generated pulsed squeezed light using the third-order nonlinear susceptibility of the semiconductor ZnS at room temperature. The photon energy was chosen to be below midgap in order to minimize nonlinear absorption. Efficient quadrature squeezing of 2.2 dB (40%) was obtained using 125 fs pulses at a center wavelength of 780 nm. The measured noise is suppressed below the quantum limit over the entire range of our detection bandwidth (30–50 MHz). The scheme employed can generally be applied to semiconductors, and opens the way for squeezed light generation over a wide range of wavelengths.
We have generated pulsed squeezed light using the third-order nonlinear susceptibility of the semiconductor ZnS at room temperature. The photon energy was chosen to be below midgap in order to minimize nonlinear absorption. Efficient quadrature squeezing of 2.2 dB (40%) was obtained using 125 fs pulses at a center wavelength of 780 nm. The measured noise is suppressed below the quantum limit over the entire range of our detection bandwidth (30-50 MHz). The scheme employed can generally be applied to semiconductors, and opens the way for squeezed light generation over a wide range of wavelengths.
Squeezed light, in which the quantum noise in one amplitude component is reduced below the vacuum level, has been generated using parametric processes. The starting point described here is the nonlinear Schrodinger equation which models light propagating through optical fibers. When such a dispersive nonlinear medium with a third-order susceptibility is pumped with an optical beam, squeezing can result. It is found that the degree of squeezing oscillates as a function of fiber length in the normal dispersion regime, whereas in the anomalous dispersion regime, it grows exponentially with fiber length. Examination of squeezing near the fiber’s zero dispersion wavelength shows that odd-order dispersive terms have no effect on squeezing. However, small values of higher-order even terms have significant effects on squeezing. In practice, high-frequency components of the squeezing spectrum are difficult to obtain. However, it is shown that a cross-correlation technique may be used to explore the frequency dependence of the squeezing spectrum.
In this dissertation measurements are presented that extend our understanding of the important noise processes involved in the semiconductor laser generation of photon-number squeezed light. Strong sub-shot noise correlations between photon-number fluctuations on orthogonal polarization axes are observed in the output of a low temperature injection-locked quantum-well laser. Such polarization dependent effects are accounted for by intrinsic correlations generated in the laser gain medium and polarization mixing due to birefringence. Using polarization preserving balanced homodyne detection, up to 4.5 dB of photon-number squeezing is reported, which is within 95% of the expected maximum squeezing based on the device quantum efficiency. The work in this dissertation demonstrates the application of such nonclassical fields to practical measurements that achieve sub-shot noise sensitivity. Coherent nonlinear optical spectroscopy with a photon-number squeezed probe field is used to measure the Urbach tail and exciton resonances in a GaAs/AlGaAs multiple quantum well with sensitivity below the semiclassical shot-noise limit. Direct drive current modulation of an injection-locked room temperature laser results in a nonclassical amplitude modulated field with a signal to noise ratio that exceeds the maximum ratio permitted for a classical source under equivalent modulation conditions.