Entanglement of movable mirror and cavity field enhanced by an optical parametric amplifier

A scheme to generate entanglement in a cavity optomechanical system filled with an optical parametric amplifier is proposed. With the help of the optical parametric amplifier, the stationary macroscopic entanglement between the movable mirror and the cavity field can be notably enhanced, and the entanglement increases when the parametric gain increases.Moreover, for a given parametric gain, the degree of entanglement of the cavity optomechanical system increases with increasing input laser power.

High-Stability High-Energy Picosecond Optical Parametric Chirped Pulse Amplifier as a Preamplifier in Nd：Glass Petawatt System for Contrast Enhancement

We demonstrate a novel picosecond optical parametric preamplification to generate high-stability, high-energy and high-contrast seed pulses. The 5ps seed pulse is amplified from 60pJ to 300μJ with an 8.6ps/ 3mJ pump laser in a signal stage of short pulse non-collinear optical parametric chirped pulse amplification. The total gain is more than 106 and the rms energy stability is under 1.35%. The contrast ratio is higher than 10s within a scale of 20ps before the main pulse. Consequently, the improvement factor of the signal contrast is approximately equal to the gain 106 outside the pump window.

Effect of the dispersion on multipartite continuous-variable entanglement in optical parametric amplifier

Based on the quantum fluctuations, we adopt the method of generalized V1 criterion to investigate multipartite entan- glement characteristics in an optical parametric amplification system with the consideration of dispersion. The nonlinear interaction becomes strong because of the existence of dispersion coefficient σ. Considering the influence of dispersion factor σ, with increasing the pump parameter μ, the value of minimum variance V1 decreases and the squeezing curve nearly equals 1/（1 ＋ μ）. The larger particle number N results in a smaller variance and higher entanglement.

Einstein-Podolsky-Rosen entanglement in time-dependent periodic pumping non-degenerate optical parametric amplifier

The solution of the time-dependent periodic pumping non-degenerate optical parametric amplifier （NOPA） is derived when the pump depletion is considered both above and below thresholds. Based on this solution, the quantum fluctuation calculated shows that a high entanglement and a good squeezing degree of the parametric light beams are achieved near and above thresholds. We adopt two kinds of pump fields： （i） a continuously modulated pump with a sinusoidal envelope; （ii） a sequence of laser pulses with Gaussian envelopes. We analyse the time evolution of continuous variable entanglement by analytical and numerical calculations, and show that the periodic driven pumping also improves the degree of entanglement. The squeezing and Einstein-Podolsky-Rosen （EPR） entanglement by using the two pumping driven functions are investigated from below to above the threshold regions, the tendencies are nearly the same, and the Caussian driven function is superior to that of the sine driven function, when the maximum squeezing and the minimum variance of quantum fluctuation are considered. In the meantime, the generalization of frequency degenerate OPA to frequency non-degenerated OPA problem is investigated.

Generation of broadly tunable picosecond mid-infrared laser and sensitive detection of a mid-infrared signal by parametric frequency up-conversion in MgO:LiNbO_3 optical parametric amplifiers

Picosecond optical parametric generation and amplification in the near-infrared region within 1.361-1.656 μm and the mid-infrared region within 2.976-4.875 μm is constructed on the basis of bulk MgO：LiNbO 3 crystals pumped at 1.064 μm.The maximum pulse energy reaches 1.3 mJ at 1.464 μm and 0.47 mJ at 3.894 μm,corresponding to a pumpto-idler photon conversion efficiency of 25%.By seeding the hard-to-measure mid-infrared radiation as the idler in the optical parametric amplification and measuring the amplified and frequency up-converted signal in the near-infrared or even visible region,one can measure very week mid-infrared radiation with ordinary detectors,which are insensitive to mid-infrared radiation,with a very high gain.A maximum gain factor of about 7 脳 10 7 is achieved at the mid-infrared wavelength of 3.374 μm and the corresponding energy detection limit is as low as about 390 aJ per pulse.

Gain Characteristics of Fiber Optical Parametric Amplifier

The theory model of fiber optical parametric amplifier (FOPA) was introduced, which is based on optical nonlinear effect. And then numerical simulation was done to analyze and discuss the gain spectral characteristics of one-pump and two-pump FOPA. The results show that for one-pump FOPA, when pump wavelength is near to fiber zero-dispersion wavelength(ZDW), the gain flatness is better, and with the increase of the pump power, fiber length and its nonlinear coefficient, the gain value will increase while the gain bandwidth will become narrow. For two-pump FOPA, when the pump central wavelength is near to fiber ZDW, the gain flatness is better. Moreover, by decreasing the space of two pumps wavelength, the gain flatness can be improved. Finally, some problems existing in FOPA were addressed.

Amplification of fluorescence using collinear picosecond optical parametric amplification at degeneracy

We demonstrate the output characteristic of broadband parametric amplification of incoherent light pulses in a 355-nm pumped degenerate picosecond optical parametric amplification with either saturated or unsaturated amplification. The optical parametric amplifier is seeded by the fluorescence generated in a solution of pyridine-1 dye in ethanol. With the saturated amplification, we can obtain high energy incoherent light pulses, whose full width at half maximum bandwidth varies from 16 nm to 53 nm for the different phase matching angles near degeneracy. Moreover, the unsaturated bandwidth of the amplified pulses fits well to the calculated result at degeneracy. Selecting s-polarized fluorescence with a Glan-Taylor prism, the maximum bandwidth of the amplified fluorescence is found to be 59 nm for a purely s-polarized seed. The maximum output energy is 0.67 mJ for the optical parametric amplifier. By using an optical filter and compressor, the generated high energy incoherent light has great potential as the incoherent pump, signal or idler wave of a parametric down-conversion process, so that a wave with a high degree of coherence can be generated from an incoherent pump light.

High-Energy Tunable 6.5-12 μm Picosecond Mid-Infrared Radiation Generated from Optical Parametric Amplifier Based on LiInSe_(2) Crystal

We report high-energy tunable 6.5-12 μm ps mid-infrared radiation generation based on OPA pumped using 1064 nm laser in LISe crystal.We simulated the relationship between the idler energy and crystal length.An optimum LISe length of 4 mm was used to enhance the idler energy experimentally.At a pump energy of ~9.4 mJ, energy levels of ~146 and of ~27 μJ are generated at 6.5 μm and 12 μm, respectively.The highest energy of ~205 μJ is achieved at 8.1 μm at a pump energy of ~19 mJ.Finally, the angular and spectral width acceptance are measured.

The influence of stimulated temperature-dependent emission cross section on intracavity optical parametric oscillator

In this paper, the influence of temperature on the intracavity optical parametric oscillator（IOPO） is investigated by using the stimulated temperature-dependent emission cross section of laser crystal. The rate equations under plane wave approximation have been used for simulation of signal output pulse. Results show that the signal output pulse width is decreased by increasing the laser crystal temperature. Also, the signal output energy is increased by the increasing of the laser crystal temperature. The simulation results for IOPO based on Nd：YAG and Nd：YVO_4, show that the signal pulse energies are increased by 3.2 and 5.6 times respectively when the laser crystal temperature increased from 15℃ to 300℃. The presented model indicates that the temperature sensitivity of Nd：YVO_4-based IOPOs is more than that of Nd：YAG-based IOPOs which is expected from a physical point of view.

High-efficiency bismuth borate-based optical parametric chirped pulse amplifier with approximately 2.1 mJ,38 fs output pulses at approximately 2150 nm

We present a compact and cost-effective mJ-level femtosecond laser system operating at a center wavelength of approximately 2.15μm.An affordable two-stage ytterbium-doped yttrium aluminum garnet(Yb:YAG)chirped pulse amplifier provides more than 10 mJ,approximately 1.2 ps pulses at 1030 nm to pump a three-stage optical parametric chirped pulse amplifier(OPCPA)based on bismuth borate crystals and to drive the supercontinuum seed in the YAG crystal.The energy of the amplified pulses in the wavelength range of 1.95–2.4μm reached 2.25 mJ with a pump-tosignal conversion efficiency of approximately 25%in the last OPCPA stage.These pulses were compressed to 38 fs in a pair of Suprasil 300 glass prisms.

MTW-OPAL:a technology development platform for ultra-intense optical parametric chirped-pulse amplification systems

Optical parametric chirped-pulse amplification implemented using multikilojoule Nd:glass pump lasers is a promising approach for producing ultra-intense pulses(>10^(23)W/cm^(2)).We report on the MTW-OPAL Laser System,an optical parametric amplifier line(OPAL)pumped by the Nd:doped portion of the multi-terawatt(MTW)laser.This midscale prototype was designed to produce 0.5-PW pulses with technologies scalable to tens of petawatts.Technology choices made for MTW-OPAL were guided by the longer-term goal of two full-scale OPALs pumped by the OMEGA EP to produce 2×25-PW beams that would be co-located with kilojoule-nanosecond ultraviolet beams.Several MTWOPAL campaigns that have been completed since“first light”in March 2020 show that the laser design is fundamentally sound,and optimization continues as we prepare for“first-focus”campaigns later this year.

Experimental investigation on pulse-contrast degradation caused by surface reflection in optical parametric chirped-pulse amplification

In this Letter, we experimentally explore the pulse-contrast degradation caused by surface reflection in optical parameter chirped-pulse amplification. Different pump-to-signal conversion efficiencies and post-pulses with different intensities are obtained by changing the seed-pulse or pump-pulse energy and inserting etalons with different reflection coefficients, respectively. The contrast measurements show that the generated first pre-pulse intensity is proportional to the product of the surface reflection intensity ratio and the square of the pump-to-signal conversion efficiency.

Analysis of ultra-broadband high-energy optical parametric chirped pulse amplifier based on YCOB crystal

A new type of optical parametric chirped pulse amplifier is designed and analyzed for the amplification of pulse centered at 808 nm. A novel crystal, yttrium calcium oxyborate YCa40（BO3）3 （YCOB）, is utilized in the power amplification stage of optical parametric amplification （OPA）. Noncollinear phase matching parameters in the xoz principle plane of YCOB, compared with those in BBO and DKDP, are analyzed by numerical simulation. The results show that YCOB rather than DKDP can be used in the power amplification stage of OPA to realize the amplification of chirped pulse to several joules with a gain bandwidth exceeding 100 nm. This can be used to gain a high intensity pulse of -10 fs after the compressor.

Generation of broadly tunable mid-infrared femtose-cond pulses by a LiNbO_3 optical parametric amplifier

Combining the configurations of collinear and small-angle noncollinear phase-matching,a mid-infrared(MIR) femtosecond optical parametric amplifier(OPA) with extended tunability is proposed and demonstrated.A tuning range from 2.0 μm to 4.7 μm is demonstrated by a two-stage LiNbO3-based femto-second OPA,which well exceeds the typical tuning range reported so far.MIR femtosecond pulses with energy up to 30 μJ are obtained.

Tunable phase-stabilized infrared parametric laser source

This paper reports that the tunable self-phase-stabilized infrared laser pulses have been generated from a two- stage optical parametric amplifier. With an 800 nm pump source, the output idler pulses are tunable from 1.3 μm to 2.3 μm, and the maximum output energy of the idler pulses is higher than I mJ at 1.6 μm by using 6 mJ pump laser. A carrier-envelope phase fluctuation of -0.15 rad （rms） for the idler pulses is measured for longer than one hour by using a home build f-to-2f interferometer.

Fiber-based optical parametric amplifier for 40-Gb/s NRZ-DPSK signal transmission system employing QC-LDPC codes

In this letter, we investigate quasi-cyclic low-density parity-check （QC-LDPC） codes in a 40-Gb/s nonreturn-to-zero differential phase-shift keying （NRZ-DPSK） signal transmission system based on a fiber- based optical parametric amplifier （FOPA）. A constructed algorithm of QC-LDPC codes according to the optimizing set of shift vMues on the circulant permutation matrix （CPM） of the basis matrix is proposed. Simulation results prove that the coding gain in the encoded system can be realized at 10.2 dB under QC- LDPC codes with a code rate of 5/6 when the bit error rate （BER） is 10-9. In addition, the error-floor level originating from the uncoded system is suppressed.

Frequency up-conversion imaging with 60-dB gain using picosecond optical parametric amplifier

A weak infrared （IR） image amplifier with more than 60-dB optical gain and is developed from a picosecond （PS） 355-nm pumped gated optical parametric frequency up-conversion amplifier （OPA） in a/% BaB204 （BBO） crystal. The IR image at 1064 nm is amplified and up-converted into the visible region at 532 nm by parametric amplification and up-conversion. With the optimized optical gain, the lowest detectable energy of the image can be as low as 1.8 femto-Joule per pulse, which is three orders of magnitude lower than the detection limit of a charge-coupled device （CCD） camera. The transversal resolution of the OPA imaging is investigated, and the approaches for higher detection sensitivity and higher transversal resolution are proposed.

Carrier-envelope phase passively stabilized near-infrared laser pulses from a dual-frequency pumped noncollinear optical parametric amplifier

By inversing the signal and idler in a two-stage noncollinear optical parametric amplifier which is,respectively,pumped by the second harmonic and fundamental wave of femtosecond Ti:sapphire laser at repetition rate of1 kHz,the carrier-envelope phase(CEP)passively stabilized pulses with a tunable wavelength from 1.1 to 1.6 lm are obtained with maximum energy of 95 lJ at 1.3 lm under the pump energy of 500 lJ.The CEP jitter of pulses is 108 mrad measured by an f-2f interferometer.This work demonstrates a new way to efficiently generate tunable near-infrared femtosecond laser pulses with self-stabilized CEP.

Nanosecond high-pulse energy 1.57 μm KTA optical parametric amplifier with time delay

An efficient two-stage KTi OAO4 optical parametric amplifier(OPA) system with walk-off-compensating alignment is designed. By introducing an extra time delay between the pump pulse and the signal pulse, this OPA architecture is capable of obtaining high optical conversion efficiency and high signal gain simultaneously.Finally, a maximum gain of 98 at the 1.57 μm wavelength is obtained with the signal beam quality of M2 around5.6. The efficiency of the optical conversion from 1.064 to 1.57 μm is around 26%.

光学参量放大器辅助的复合腔磁系统中磁力诱导透明及快慢光效应

提出了一种含有光学参量放大器的复合腔磁系统。利用系统海森堡-郎之万演化方程和输入-输出关系研究了磁力诱导透明和快慢光效应。数值计算表明:当腔磁系统考虑磁振子-声子耦合时,出现双重透明窗口。磁振子-声子之间的耦合强度增强,透明窗口宽度变宽,深度加深。在系统中调控光学参量放大器的增益,吸收光谱在共振频率两侧出现不对称现象,吸收谱曲线的峰值随光学参量放大器增益的增加而变大。通过调节腔磁耦合强度,改变了吸收光谱和色散光谱的传输特性。此外,探测场的传输速率依赖于光学参量放大器的增益。腔磁系统的快慢光效应及其切换通过调控光学参量放大器得以实现。该研究结果可为量子光学操纵和量子信息存储的研究提供参考。