Soft proton exchanged channel waveguides in congruent lithium tantalate for frequency doubling

We report on stable optical waveguides fabricated by soft-proton exchange in periodically-poled congruent lithium tantalate in the α-phase. The channel waveguides are characterized in the telecom wavelength range in terms of both linear properties and frequency doubling. The measurements yield a nonlinear coefficient of about 9.5pm/V, demonstrating that the nonlinear optical properties of lithium tantalate are left nearly unaltered by the process

Ultra-compact amorphous silicon waveguide for wavelength conversion

In this work we demonstrate, for the first time, successful four wave mixing (FWM) based wavelength conversion of Binary Phase Shift Keyed (BPSK) and Quadrature Phase Shift Keyed (QPSK) signals, at 20 Gb/s bitrate, in a 1-mm long amorphous silicon waveguide. A maximum FWM-efficiency of -26 dB was achieved by employing a pump power of just 70 mW, establishing this technology as a contender for the development of ultra-compact, low power, silicon photonics wavelength converter. Bit Error Ratio (BER) measurements demonstrated successful conversion with less than 1 dB penalty level, for both BPSK and QPSK signals (at BER = 10-5)

Roadmap for Optical Tweezers 2023

Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nanoparticle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration

Le Pinze ottiche: un potente strumento per la micromanipolazione senza contatto fisico

Le pinze ottiche sono uno strumento che permette di intrappolare e muovere senza contatto fisico particelle di dimensioni nanometriche e micrometriche. Il loro funzionamento si basa sulla pressione di radiazione esercitata da fasci laser che, se opportunamente focalizzati, producono un punto di equilibrio stabile di forze in corrispondenza del fuoco che viene denominato trappola ottica. Gli apparati per la realizzazione di pinze ottiche sono tipicamente basati su microscopi opportunamenti modificati e dotati di un obiettivo ad altissima apertura numerica che garantisce la forte focalizzazione necessaria per l’intrappolamento. Tali apparati hanno gi`a dimostrato di avere grandi potenzialit`a in parecchi campi, principalmente in ambito biologico, in quanto rappresentano un metodo di manipolazione estremamente calibrato, non invasivo e completamente sterile di singole cellule o organelli subcellulari. Malgrado cio', le pinze ottiche basate su microscopio soffrono di alcune limitazioni legate principalmente all’ingombro e alla complessita' della struttura. Per questo negli anni recenti e' stato rivolto un crescente interesse allo sviluppo di pinze basate su fibra ottica che permettono di ottenere uno strumento miniaturizzato, semplice, flessibile e a basso costo. In questo articolo verra' illustrato un nuovo approccio alla realizzazione di una pinza ottica in fibra che e' stato sperimentalmente dimostrato presso il Laboratorio di Elettronica Quantistica dell’Universita' di Pavia in collaborazione con il laboratorio BIONEM dell’Universita' della Magna Graecia di Catanzaro. La nuova pinza ottica ha permesso di ottenere per la prima volta un intrappolamento tridimensionale di particelle micrometriche ad elevata distanza di lavoro (≈ 40 μm) e rappresenta un promettente strumento per l’indagine biomedica

Photonics: a short course

This book will serve as a concise, self-contained, up-to-date introduction to Photonics, to be used as a textbook for undergraduate students or as a reference book for researchers and professionals. Blending theory with technical descriptions, the book covers a wide range of topics, including the general mechanism of laser action, continuous and pulsed laser operation, optical propagation in isotropic and anisotropic media, operating principles and structure of passive optical components, electro-optical and acousto-optical modulation, solid-state lasers, semiconductor lasers and LEDs, nonlinear optics, and optical fiber components and devices.. The book concludes with an overview of applications, including optical communications, telemetry and sensing, industrial and biomedical applications, solid-state lighting, displays, and photovoltaics