Manuel Caño-Garcia

Universidad Politécnica de Madrid | UPM · Departamento de Tecnología Fotónica y Bioingeniería (TFB)

Nanoimprint lithography (NIL) is an imprinting technique which has experienced an increasing popularity due to its versatility in fabrication processes. Commercial NIL machines are readily available achieving high quality results; however, these machines involve a relatively high investment. Hence, small laboratories often choose to perform NIL cop...

In this work, the performance of a Mach–Zehnder interferometer manufactured in silicon nitride with a liquid crystal cladding is studied. The device consists of two multi-mode interference couplers linked by two rectangular waveguides, the cladding of one of which is a liquid crystal. The structure demonstrates the potential of using liquid crystal...

A new concept of thin, flat, transparent variable lenses with unprecedented performance in terms of active diameter and focal distance range is presented. The diffractive lens consists of two cascaded variable liquid crystal‐based spiral diffractive lenses. Changing concertedly the topological charge changes the focal length with no mechanical moti...

This work demonstrates an integrated multimode interferometer (MMI) based on a fully polymeric platform and optimized for visible range operation. The dimensions of a 2×2 MMI are first calculated analytically and simulated using finite elements method. The devices are manufactured using two layers of negative tone photoresists. The top layer is pat...

Polymer based photonic devices offer the possibility cost effective roll-to-roll manufacture of photonic devices. The incorporation of luminescent dopants within a solid polymer waveguide allows for the generation of light within the device avoiding tedious mechanical light coupling. However, when a dopant is embedded in a solid matrix, depending o...

Optical beam steering (BS) has multiple applications in fields like target seeking and tracking, optical tweezers, billboard displays and many others. In this work, a two-dimensional beam deflector based on blaze gratings is presented. Phase-only 1D blaze gratings have been prepared using maskless Direct Laser Writing (DLW) resulting in high-resolu...

Quantum random walks use interference to obtain faster state space exploration, which can be used for algorithmic purposes. Photonic technologies provide a natural platform for many recent experimental demonstrations. Here we analyze quantum random walks implemented by coherent light propagation in series-coupled photonic ring resonators. We propos...

Polymer based photonic devices offer the possibility cost effective roll-to-roll manufacture of photonic devices. The incorporation of luminescent dopants within a solid polymer waveguide allows for the generation of light within the device avoiding tedious mechanical light coupling. However, when a dopant is embedded in a solid matrix, depending o...

A compact and cost effective NIR-VIS-UV lidar echo emulator (LEE) was designed and manufactured as a compact breadboard. The LEE is an application specific optical pulse shaper delivering a short lidar return (echo) in the ns range overlapped with a long lidar return in the µs range with a repetition rate from 100 Hz – 500 Hz. The short echo power...

The recently developed Lorentz Oscillator Model-inspired Oscillator Finite-Difference Time-Domain (O-FDTD) is one of the simplest FDTD models ever proposed, using a single field equation for electric field propagation. We demonstrate its versatility on various scales and benchmark its simulation performance against theory, conventional FDTD simulat...

Electric field mapping simulation software based on the novel Oscillation - Finite Difference Time Domain (O-FDTD) method ( https://doi.org/10.1364/OE.414211 ). This package contains a Graphical User Interface (GUI)-powered Toolbox for MATLAB for designing and running simulations. Please contact the authors if interested in the raw code.

We use femtosecond laser-based two-photon polymerization (TPP) to fabricate a 2.5D micropillar array. Using an angular detection setup, we characterize the structure's scattering properties and compare the results against simulation results obtained from a novel electrodynamics simulation method. The algorithm employs a modified formulation of the...

A project-based teaching course for postgraduate students in the field of Photonics Engineering is based on the implementation of a Spectrophotometer. Hard and soft skills are evaluated in the implementation with an auto-evaluation criteria.

The ALL project has brought together lens technology developed at a public university with an SME with experience in commercial liquid crystal electronics. The patented lens technology is based on cascading liquid crystal devices inducing optical vortices. Changing the electric addressing of the cascaded devices changes the lens focal length. The r...

In the previous chapter, we have browsed upon the optics of photographic cameras, focusing on the specific features of digital cameras and their sensors. We have also compared the camera performance with eye, including grayscale, sensitivity, dynamic range, field of view and many others. Eyes are far superior to cameras inseveral aspects, those fav...

Over the last half century, photography has evolved from photochemical reactions induced on a photosensitive film to optoelectronic devices employed in digital image. Video has done the same migration from classical film movies to optoelectronic acquisition and storage. Digitaland videocameras share optics with traditional film cameras, but the ima...

Nowadays, the development of new devices based on liquid crystal (LC) materials requires improved tuning characteristics according to the application. One approach for this improvement is the use of nanomaterials with the capability of modifying the effective properties of the doped LC mixture. In this work, we analyze the electrical behavior of a...

The construction of a low-cost spectrophotometer as part of project-based teaching for postgraduate students in the field of Photonics Engineering is depicted. The criteria followed in designing this project include considerations about budget, portability and multidisciplinary skills. The proposal has been carried out in the context of a 3 credit...

Optical waveguides in photonic integrated circuits are traditionally passive elements merely carrying optical signals from one point to another. These elements could contribute to the integrated circuit functionality if they were modulated either by variations of the core optical properties, or by using tunable claddings. In this work, the use of l...

The atomic force microscope (AFM) is an extremely useful instrument for characterization of microstructures. Its high cost precludes a more general utilization especially among small research groups, which have to request services from third parties. Several AFM projects have been recently published on open source platforms, paving the way to the r...

Photonic integrated circuits (PICs) have so far got a quite modest integration level. There is a growing interest on the concept of PICs having enhanced functionality while keeping or moderately increasing their complexity. One possible route to this goal is to develop active waveguides within the PICs, by including electrooptical devices that can...

Lyotropic liquid crystals play an important role in many biological environments, such as micelles, liposomes, and phospholipid bilayers of cell membranes. In this work, we explore the performance of lyotropic liquid crystals as biosensors for macromolecules, proteins and whole microorganisms in hydrophilic media, i.e., the natural media where thes...

The design and characterisation of a reconfigurable multi-level spiral phase plate is shown. The device is based on a pie-shape liquid-crystal structure with 24 slices driven by custom electronics that allow independent excitation control of each electrode. The electrooptical cell was manufactured using maskless laser ablation lithography and has s...

Nanoimprint lithography has become a useful tool to prepare elements containing nanoscale features at quite reasonable cost, especially if the fabrication elements are created in the own laboratory. We have designed and fabricated a whole nanoimprint manufacturing system and analyzed the resulting surfaces using ad hoc packages developed on an open...

This paper reports on the design, fabrication and characterization of an all-organic photonic integrated circuit working as a switching polarizer for visible light (630nm), combining organic waveguides and liquid crystals that can be electrically driven. The device was made in commercially available epoxy by laser direct writing lithography. A devi...

A simple in-layer electro optical switch has been prepared by selectively curing a photocurable optical polymer with a UV laser. The core of the device is a NOA-81 multimode waveguide grown by selective laser curing. The cladding is a positive calamitic liquid crystal, which allows tunability and switching of the waveguide by external driving elect...

Policryps structures of photo-curable adhesive NOA61 and nematic liquid crystal mixture E7 have been created inside selected microchannels of photonic crystal fibers (PCF). The PCF was selectively infiltrated with the photopolymer-liquid crystal mixture for the writing of a holographic tunable grating inside specific holes of the photonic fiber. A...

A photonic integrated circuit (PIC) or integrated optical circuit is a device that integrates multiple (at least two) photonic functions, being as such similar to electronic integrated circuits. The connections between components are made of light waveguides; these can be active themselves –i.e., light paths can be externally controlled– by using e...

Traditionally, the reproduction of patterns with micron of submicron features has been a matter of expensive microelectronic equipments and involved processes. Nanoprinting machines, usually employed for polymer castings, are a good example of these equipments. Nevertheless, it is possible to develop simple processes to make micron-size patterns in...

Photonic integrated circuits (PICs) are devices that integrate multiple photonic functions. The visible light is guided between components by light waveguides of the same order as light wavelength, i.e. 1-5μm or even less [1]. Because of the size of connections, coupling light into PICs is a challenging task previous to characterizing them. The aim...

An experimental results on birefringent photonic crystal fiber (PCF) selectively infiltrated with metallic nanoparticles (NPs) dispersed in polydimethylsiloxane (PDMS) are presented. In general, PCFs are structures consisting of periodic matrix of microholes surrounding core region, that can be either solid or hollow. The PCSs structure can be infi...

Microbial contamination of food, water and even air supply is a permanent threat against the health of humans and livestock. This threat is particularly serious in contexts such as hospitals (Legionella contamination of air-conditioning) and in extreme situations, such as those met in the third world and in natural crisis situations where water con...

A photonic integrated circuit (PIC) or integrated optical circuit is a device that integrates multiple (at least two) photonic functions, being as such similar to electronic integrated circuits. The connections between components are made of light waveguides; these can be active themselves –i.e., light paths can be externally controlled– by using e...

Coupling light into a photonic integrated circuit (PIC) is usually the most challenging task to characterize these circuits. PIC connections between components are made of light waveguides whose section is often of the same order as light wavelength, i.e., 1-5 μm or even less. Waveguides may become active by inserting additional layers of electroop...

The Polarization Maintaing Photonic Crystal Fiber PM-1550-01 has been employed to create intermodal interferometers by splicing short (cm) portions of PCF between two single mode fiber (SMF) pigtails and PANDA fibers. It has been shown that this setup generates a intermodal interferometer. The interferometers have been made tunable by the inclusion...

Liquid crystal devices are increasingly being used in non-display applications to manufacture small devices that can be driven by low voltage electronics. LCs are low cost, light weight and avoid using mechanical components. A wide number of interesting applications involve the use of LCs for phase modulation of light. This can be done with light p...

The peculiar optical response of polydimethylsiloxane (PDMS) doped with metallic nanoparticles can be employed to develop optical sensing materials. These nanocomposites may work in an ample range of temperatures, showing good linearity and high sensitivity. Plasmon resonances of the metallic nanoparticles produce interesting effects on the optical...

A photonic crystal fiber selectively filled with silver nanoparticles dispersed in polydimethylsiloxane has been numerically studied via finite elements analysis. These nanoparticles possess a localized surface plasmon resonance in the visible region which depends on the refractive index of the surrounding medium. The refractive index of polydimeth...

Many photonic devices are based on waveguides (WG) whose optical properties can be externally modified. These active WGs are usually obtained with electrooptic materials in either the propagating film (core) or the substrate (cladding). In the second case, the WG tunability is based on the interaction of the active material with the evanescent fiel...