Summary form only given. Quadratic non-linear interaction is known to support the process of spatial soliton formation. A very simple set-up consists of a single pass, single crystal, quantum noise optical parametric amplifier (OPA) pumped by a focussed beam. The diffraction-free propagation achieved in the solitary-wave regime implies that the beam-waist plane of the pump beam can arbitrarily move inside the crystal without any relevant change in the size of the mutually trapped pump, signal and idler beams at the crystal output face. We present a very useful application of this property to the reconstruction of digital images. The experimental set-up is based on a 30 mm temperature tuned lithium triborate (LBO) crystal, operated in noncritical type I phase matching and pumped by a 15 ps, 527 nm pulse from an amplified frequency doubled Nd:glass laser. We set the crystal temperature to 107/spl deg/C to obtain generation at 1.8 /spl mu/m (idler) and 0.75 /spl mu/m (signal), ensuring minimum group velocity mismatch among interacting pulses.Summary form only given. Quadratic non-linear interaction is known to support the process of spatial soliton formation. A very simple set-up consists of a single pass, single crystal, quantum noise optical parametric amplifier (OPA) pumped by a focussed beam. The diffraction-free propagation achieved in the solitary-wave regime implies that the beam-waist plane of the pump beam can arbitrarily move inside the crystal without any relevant change in the size of the mutually trapped pump, signal and idler beams at the crystal output face. We present a very useful application of this property to the reconstruction of digital images. The experimental set-up is based on a 30 mm temperature tuned lithium triborate (LBO) crystal, operated in noncritical type I phase matching and pumped by a 15 ps, 527 nm pulse from an amplified frequency doubled Nd:glass laser. We set the crystal temperature to 107/spl deg/C to obtain generation at 1.8 /spl mu/m (idler) and 0.75 /spl mu/m (signal), ensuring minimum group velocity mismatch among interacting pulses.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Nov 11, 20020 citations

Experimental Generation and Characterization of Multimode Squeezed Light in a Synchronously Pumped Optical Parametric Oscillator

Edoardo Suerra, Francesco Canella, Dario Giannotti +3 more

Multimode squeezed light is a key resource for quantum technologies, enabling applications in boson sampling, quantum networks, and optical quantum computation [1],[2]. Parametric down-conversion in synchronously pumped optical parametric oscillators (SPOPOs) offers a versatile platform for generating multimode squeezed states across the time-frequency domain. In these systems, supermodes manifest as independent quantum states in the temporal domain and as frequency combs in the spectral domain [3]. Precise control of these states is crucial for quantum applications and requires an experimental setup capable of fine-tuning multiple parameters to optimize squeezing properties. In this work, we present an experimental setup for generating and characterizing multimode vacuum squeezed states using a SPOPO and a balanced homodyne detection scheme. Two spatial light modulators (SLMs) placed on the pump and local oscillator (LO) beams provide full control over their spectral properties, including amplitude and phase shaping. This flexibility allows us to optimize the experimental conditions and investigate squeezing dependence on key parameters such as the LO spectral detuning and bandwidth. By introducing a programmable $\pi$ -phase shift to the LO via the SLM, we selectively probe the multimode structure, distinguishing between even and odd supermodes. Additionally, the SLM on the pump can introduce an arbitrary chirp, further enhancing control over the system. Our setup, schematized in Figure 1a, is based on a commercial mode-locked Yb-fiber laser operating at 93MHz, emitting pulses centered at 1035nm with a 10nm bandwidth. A portion of the radiation is frequency-doubled to 517.5nm via an LBO crystal to serve as the pump for the SPOPO, while the remaining part is used as the LO for homodyne detection after transmission through the SPOPO cavity, ensuring high beam quality. The SPOPO cavity is frequency-locked to the laser via a Pound-Drever-Hall technique, ensuring stable and optimized operation. Figure 1b presents representative measurements of squeezing levels as a function of the LO spectral bandwidth, showing how its symmetric or antisymmetric phase influences the detection of different supermodes and, consequently, the squeezing level depending on their structure. The measurements were performed using lithium niobate (LNB) nonlinear crystals of 3.0mm and 1.5mm lengths. Our setup allows for future investigations of dispersion effects on squeezing, thus far only theoretically predicted [4], by introducing chirped mirrors for dispersion compensation. Moreover, different nonlinear crystals, such as lithium niobate, beta barium borate (BBO), and lithium triborate (LBO) of various lengths, will be tested to explore the multimode properties of the squeezed states. These investigations will provide insights into the experimental conditions required to achieve single-mode squeezing, crucial for applications such as Gaussian Boson Sampling, with results to be presented at the conference.Multimode squeezed light is a key resource for quantum technologies, enabling applications in boson sampling, quantum networks, and optical quantum computation [1],[2]. Parametric down-conversion in synchronously pumped optical parametric oscillators (SPOPOs) offers a versatile platform for generating multimode squeezed states across the time-frequency domain. In these systems, supermodes manifest as independent quantum states in the temporal domain and as frequency combs in the spectral domain [3]. Precise control of these states is crucial for quantum applications and requires an experimental setup capable of fine-tuning multiple parameters to optimize squeezing properties. In this work, we present an experimental setup for generating and characterizing multimode vacuum squeezed states using a SPOPO and a balanced homodyne detection scheme. Two spatial light modulators (SLMs) placed on the pump and local oscillator (LO) beams provide full control over their spectral properties, including amplitude and phase shaping. This flexibility allows us to optimize the experimental conditions and investigate squeezing dependence on key parameters such as the LO spectral detuning and bandwidth. By introducing a programmable$\pi$-phase shift to the LO via the SLM, we selectively probe the multimode structure, distinguishing between even and odd supermodes. Additionally, the SLM on the pump can introduce an arbitrary chirp, further enhancing control over the system. Our setup, schematized in Figure 1a, is based on a commercial mode-locked Yb-fiber laser operating at 93MHz, emitting pulses centered at 1035nm with a 10nm bandwidth. A portion of the radiation is frequency-doubled to 517.5nm via an LBO crystal to serve as the pump for the SPOPO, while the remaining part is used as the LO for homodyne detection after transmission through the SPOPO cavity, ensuring high beam quality. The SPOPO cavity is frequency-locked to the laser via a Pound-Drever-Hall technique, ensuring stable and optimized operation. Figure 1b presents representative measurements of squeezing levels as a function of the LO spectral bandwidth, showing how its symmetric or antisymmetric phase influences the detection of different supermodes and, consequently, the squeezing level depending on their structure. The measurements were performed using lithium niobate (LNB) nonlinear crystals of 3.0mm and 1.5mm lengths. Our setup allows for future investigations of dispersion effects on squeezing, thus far only theoretically predicted [4], by introducing chirped mirrors for dispersion compensation. Moreover, different nonlinear crystals, such as lithium niobate, beta barium borate (BBO), and lithium triborate (LBO) of various lengths, will be tested to explore the multimode properties of the squeezed states. These investigations will provide insights into the experimental conditions required to achieve single-mode squeezing, crucial for applications such as Gaussian Boson Sampling, with results to be presented at the conference.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Jun 23, 20250 citations

Frequency-filtered parametric fluorescence interacting with an atomic ensemble

K. Akiba, Daisuke Akamatsu, Mikio Kozuma

Optics CommunicationsNov 11, 20053 citations

Experimental Investigation of Intensity Difference Squeezing at 1.3 μm-Quantum Communication Window

郑耀辉 Zheng Yaohui

The stable red laser,which is generated by the laser at 1.3 μm wavelength from an all-solid-state single frequency infrared laser pumping a frequency-doubler,is used to pump a continuous wave nondegenerate optical parametric oscillator(cw-NOPO) consisting of LBO crystal with type-Ⅱ non-critical phase matching.The intensity-difference squeezing of 3.9 dB at a telecommunication wavelength has been generated from the cw-NOPO operating above the oscillation threshold through the frequency down-conversion process.The stable red laser,which is generated by the laser at 1.3 μm wavelength from an all-solid-state single frequency infrared laser pumping a frequency-doubler,is used to pump a continuous wave nondegenerate optical parametric oscillator(cw-NOPO) consisting of LBO crystal with type-Ⅱ non-critical phase matching.The intensity-difference squeezing of 3.9 dB at a telecommunication wavelength has been generated from the cw-NOPO operating above the oscillation threshold through the frequency down-conversion process.

Acta Sinica Quantum OpticaJan 1, 20100 citations

\pi

-phase shift to the LO via the SLM, we selectively probe the multimode structure, distinguishing between even and odd supermodes. Additionally, the SLM on the pump can introduce an arbitrary chirp, further enhancing control over the system. Our setup, schematized in Figure 1a, is based on a commercial mode-locked Yb-fiber laser operating at 93MHz, emitting pulses centered at 1035nm with a 10nm bandwidth. A portion of the radiation is frequency-doubled to 517.5nm via an LBO crystal to serve as the pump for the SPOPO, while the remaining part is used as the LO for homodyne detection after transmission through the SPOPO cavity, ensuring high beam quality. The SPOPO cavity is frequency-locked to the laser via a Pound-Drever-Hall technique, ensuring stable and optimized operation. Figure 1b presents representative measurements of squeezing levels as a function of the LO spectral bandwidth, showing how its symmetric or antisymmetric phase influences the detection of different supermodes and, consequently, the squeezing level depending on their structure. The measurements were performed using lithium niobate (LNB) nonlinear crystals of 3.0mm and 1.5mm lengths. Our setup allows for future investigations of dispersion effects on squeezing, thus far only theoretically predicted [4], by introducing chirped mirrors for dispersion compensation. Moreover, different nonlinear crystals, such as lithium niobate, beta barium borate (BBO), and lithium triborate (LBO) of various lengths, will be tested to explore the multimode properties of the squeezed states. These investigations will provide insights into the experimental conditions required to achieve single-mode squeezing, crucial for applications such as Gaussian Boson Sampling, with results to be presented at the conference.