Optical realization of the dissipative quantum oscillator

An optical realization of the damped quantum oscillator, based on transverse light dynamics in an optical resonator with slowly-moving mirrors, is theoretically suggested. The optical resonator setting provides a simple implementation of the time-dependent Caldirola-Kanai Hamiltonian of the dissipative quantum oscillator, and enables to visualize the effects of damped oscillations in the classical (ray optics) limit and wave packet collapse in the quantum (wave optics) regime.Comment: The article is dedicated to Professor Orazio Svelto on the occasion of his 80th birthday. To appear in Optics Letter

Micro-Hole Generation by High-Energy Pulsed Bessel Beams in Different Transparent Materials

Micro-drilling transparent dielectric materials by using non-diffracting beams impinging orthogonally to the sample can be performed without scanning the beam position along the sample thickness. In this work, the laser micromachining process, based on the combination of picosecond pulsed Bessel beams with the trepanning technique, is applied to different transparent materials. We show the possibility to create through-apertures with diameter on the order of tens of micrometers, on dielectric samples with different thermal and mechanical characteristics as well as different thicknesses ranging from two hundred to five hundred micrometers. Advantages and drawbacks of the application of this technique to different materials such as glass, polymer, or diamond are highlighted by analyzing the features, the morphology, and the aspect-ratio of the through-holes generated. Alternative Bessel beam drilling configurations, and the possibility of optimization of the quality of the aperture at the output sample/air interface is also discussed in the case of glass

Femtosecond laser inscription of nonlinear photonic circuits in Gallium Lanthanum Sulphide glass

We report on femtosecond laser writing of single mode optical waveguides in chalcogenide Gallium Lanthanum Sulphide (GLS) glass. A multiscan fabrication process was employed to create waveguides with symmetric single mode guidance and low insertion losses at 800 nm wavelength, compatible with Ti:Sapphire ultrafast lasers. {\mu}Raman and X-Ray microanalysis were used to elucidate the origin of the laser-induced refractive index change in GLS. Nonlinear refractive index measurements of the waveguides were performed by finding the optical switching parameters of a directional coupler, demonstrating that the nonlinear properties were preserved, evidencing that GLS is a promising platform for laser-written integrated nonlinear photonics

Metal and Metal Oxide Transformation and Texturing Using Pulsed Fiber Laser

Thin films of amorphous vanadium metal were deposited on a glass substrate using the electron beam evaporator, these thin films were then exposed to a focused 1064 nm wavelength nanosecond laser pulses. The laser fluence was selected such that it was below the ablation threshold of the films, x-ray diffraction measurement revealed the formation of an oxide phase of vanadium after the laser exposure. The time of flight-secondary ion mass spectrometry data analysis showed a uniform elemental distribution of the elements on the films, whereas the Rutherford backscattering spectrometry results showed that the concentration of oxygen as a function of the laser fluence was increasing, hinting to the incorporation of the oxygen atoms in the films as the laser fluence increases. UV-Vis-NIR percentage reflectance measurements showed small evolution in the visible part of the spectrum due to laser exposure

Optical NP problem solver on laser-written waveguide platform

Cognitive photonic networks are researched to efficiently solve computationally hard problems. Flexible fabrication techniques for the implementation of such networks into compact and scalable chips are desirable for the study of new optical computing schemes and algorithm optimization. Here we demonstrate a femtosecond laser-written optical oracle based on cascaded directional couplers in glass, for the solution of the Hamiltonian path problem. By interrogating the integrated photonic chip with ultrashort laser pulses, we were able to distinguish the different paths traveled by light pulses, and thus infer the existence or the absence of the Hamiltonian path in the network by using an optical correlator. This work proves that graph theory problems may be easily implemented in integrated photonic networks, down scaling the net size and speeding up execution times

Quantum micro–nano devices fabricated in diamond by femtosecond laser and ion irradiation

Diamond has attracted great interest as a quantum technology platform thanks to its optically active nitrogen vacancy (NV) center. The NV's ground state spin can be read out optically, exhibiting long spin coherence times of ≈1 ms even at ambient temperatures. In addition, the energy levels of the NV are sensitive to external fields. These properties make NVs attractive as a scalable platform for efficient nanoscale resolution sensing based on electron spins and for quantum information systems. Diamond photonics enhance optical interactions with NVs, beneficial for both quantum sensing and information. Diamond is also compelling for microfluidic applications due to its outstanding biocompatibility, with sensing functionality provided by NVs. However, it remains a significant challenge to fabricate photonics, NVs, and microfluidics in diamond. In this Progress Report, an overview is provided of ion irradiation and femtosecond laser writing, two promising fabrication methods for diamond‐based quantum technological devices. The unique capabilities of both techniques are described, and the most important fabrication results of color center, optical waveguide, and microfluidics in diamond are reported, with an emphasis on integrated devices aiming toward high performance quantum sensors and quantum information systems of tomorrow

Pulsed Bessel beam-induced microchannels on a diamond surface for versatile microfluidic and sensing applications

We present a laser machining method based on the use of pulsed Bessel beams to create, by single pass transverse writing, three-dimensional trench-like microstructures on a synthetic monocrystalline diamond substrate. By tuning the laser pulse energy and the writing speed, it is possible to control the features of the surface trenches obtained and to optimize the resulting high aspect-ratio and low roughness microstructures. This work confirms the potentialities of quasi-stationary beams in ultra-fast laser inscription technology. In particular the presented results show the possibility to fabricate deep and precise microfluidic channels on biocompatible diamond substrates, offering a great potential for biomedical sensing applications

On-chip single-photon subtraction by individual silicon vacancy centers in a laser-written diamond waveguide

Modifying light fields at single-photon level is a key challenge for upcoming quantum technologies and can be realized in a scalable manner through integrated quantum photonics. Laser-written diamond photonics offers three-dimensional fabrication capabilities and large mode-field diameters matched to fiber optic technology, though limiting the cooperativity at the single-emitter level. To realize large cooperativities, we combine excitation of single shallow-implanted silicon vacancy centers via large numerical aperture optics with detection assisted by laser-written type-II waveguides. We demonstrate single-emitter extinction measurements with a cooperativity of 0.153 and a beta factor of 13% yielding 15.3% as lower bound for the quantum efficiency of a single emitter. The transmission of resonant photons reveals single-photon subtraction from a quasi-coherent field resulting in super-Poissonian light statistics. Our architecture enables single quantum level light field engineering in an integrated design which can be fabricated in three dimensions and with a natural connectivity to optical fiber arrays.Comment: 8 pages, 4 figure