Jesús Lancis

Universitat Jaume I | UJI · Department of Physics

We present a single-pixel microscope with optical sectioning by combining two structured illumination methods: structured illumination microscopy (SIM) and single-pixel imaging (SPI). Experimental results are shown for the application in 3D fluorescence microscopy by scanning different axial planes.

We present a system for imaging objects through non-homogeneous scattering media that works in an adaptive way by combining diffuse optical imaging (DOI) and single-pixel imaging (SPI) techniques. The experimental results are shown.

We present a spatial frequency domain imaging (SFDI) system based on single- pixel imaging (SPI) techniques with a single digital micromirror device (DMD) modulating simultaneously the sinusoidal pattern and the spatial sampling masks.

Multifunctional triple color photoluminescent (PL) nitrogen–boron doped carbon quantum dots (CQDs) with high quantum yield (QY) of 58% are fabricated by one step femtosecond pulsed laser irradiation of a single precursor (2‐aminopyrimidine‐5‐boronic acid) in solution. In situ generated non‐linear and linear emissions are used to monitor CQDs format...

There exists an increasing demand of industrial-scale production of high-purity ligand-free nanoparticles due to the continuous development of biomedicine, catalysis, and energy applications. In this contribution, a simultaneous spatial and temporal focusing (SSTF) setup is first proposed for increasing nanoparticle productivity of the eco-friendly...

Imaging the retina of cataractous patients is useful to detect pathologies before the cataract surgery is performed. However, for conventional ophthalmoscopes, opacifications convert the lens into a scattering medium that may greatly deteriorate the retinal image. In this paper we show, as a proof of concept, that it is possible to surpass the limi...

In nonlinear microscopy, phase-only spatial light modulators (SLMs) allow achieving simultaneous two-photon excitation and fluorescence emission from specific region-of-interests (ROIs). However, as iterative Fourier transform algorithms (IFTAs) can only approximate the illumination of selected ROIs, both image formation and/or signal acquisition c...

In wide-field nonlinear microscopy, wavefront modulation by means of phase-only spatial light modulators (SLMs) allows achieving simultaneous two-photon excitation and fluorescence emission from specific region-of-interests (ROIs) of biological specimens. This is basically accomplished at the illumination path of the microscope by the reconstructio...

Single-pixel cameras (SPCs) have been successfully used in different imaging applications during the last decade. In these techniques, the scene is illuminated with a sequence of microstructured light patterns codified onto a programmable spatial light modulator. The light coming from the scene is collected by a bucket detector, such as a photodiod...

We present a novel approach for imaging through scattering media that combines the principles of Fourier spatial filtering and single-pixel imaging. We compare the performance of our single-pixel imaging setup with that of a conventional system. Firstly, we show that a single-pixel camera does not reduce the frequency content of the object, even wh...

A single-pixel digital holography system with phase-encoded illumination using a digital micromirror device (DMD) as a spatial light modulator (SLM) is presented. The enhanced switching rate of DMDs, far exceeding the stringent frame-rate of liquid crystal SLMs, allows recording and reconstruction of complex amplitude distributions in just a few se...

We propose a method to perform color imaging with a single photodiode by using light structured illumination generated with a low-cost color LED array. The LED array is used to generate a sequence of color Hadamard patterns which are projected onto the object by a simple optical system while the photodiode records the light intensity. A field progr...

We present a novel approach for imaging through turbid media that combines the principles of Fourier spatial filtering with single-pixel imaging. We compare the performance of our single-pixel imaging setup with that of a conventional system. We conclude that the introduction of Fourier gating improves the contrast of images in both cases. Furtherm...

Single-pixel cameras have been successfully used in different imaging applications in the last years. One of the key elements affecting the quality of these cameras is the photodetector. Here, we develop a numerical model of a single-pixel camera, which takes into account not only the characteristics of the incident light but also the physical prop...

We experimentally demonstrate Fresnel holograms able to produce multifocal irradiance patterns with micrometric spatial resolution. These holograms are assessed from the coherent sum of multiple Fresnel lenses. The utilized encoded technique guarantees full control over the reconstructed irradiance patterns due to an optimal codification of the amp...

Single-pixel detection approaches have been applied with success in different imaging techniques such as optical microscopy. Here we show that it is possible to improve the resolution of single-pixel microscopy by using an array of photodetectors and Fourier ptychography algorithms.

Harvesting solar radiation should be improved to make this type of renewable energy more competitive in economic terms. Furthermore, to develop “green” nanotechnology is a prerequisite for crossing the boundary between research and industrial applications. In this contribution we will show the synthesis of a solar nanofluid of tin with ethylene gly...

We describe, through simulations and experiments, a real-time wavefront acquisition technique using random binary amplitude masks and an iterative phase retrieval algorithm based on the Fresnel propagator. By using a digital micro-mirror device, it is possible to recover an unknown complex object by illuminating with this set of masks and simultane...

We demonstrate imaging of complex amplitude objects through digital holography with phase-structured illumination and bucket detection. The object is sampled with a set of micro-structured phase patterns implemented onto a liquid-crystal spatial light modulator while a bucket detector sequentially records the irradiance fluctuations corresponding t...

In the last years, single-pixel imaging (SPI) was established as a suitable tool for non-invasive imaging of an absorbing object completely embedded in an inhomogeneous medium. One of the main characteristics of the technique is that it uses very simple sensors (bucket detectors such as photodiodes or photomultiplier tubes) combined with structured...

This work describes a phase reconstruction technique by using a short number of random binary amplitude masks projected using a digital micromirror device (DMD) and an iterative algorithm including the Fresnel propagation equation. The technique provides short recording and caculation times, taking advantage of the high frame rates of the DMD (abov...

Solar energy is extended over wide geographical areas and is becoming an essential tool to keep the ever-increasing demand of energy with minimal environmental impact. A solar nanofluid is a novel solar receiver concept for efficient harvesting of solar radiation based on volumetric absorption of directly irradiated nanoparticles in a heat transfer...

We propose a simple and robust method to determine the calibration function of phase-only spatial light modulators (SLMs). The proposed method is based on the codification of binary phase Fresnel lenses (BPFLs) onto an SLM. At the principal focal plane of a BPFL, the focal irradiance is collected with a single device just able to measure intensity-...

Ophthalmoscopes to image the retina are widely used diagnostic tools in ophthalmology and are vital for the early detection of many eye diseases. Although there are various effective optical implementations of ophthalmoscopes, new, robust systems may have a future practical importance in cases where ocular media present significant opacities. Here,...

We present a novel approach for retinal imaging based on a single pixel detector combined with a fast multiplexed illumination. The instrument operates in real-time and is tolerant to various ocular conditions which would normally downgrade image quality compared to similar fundus imaging devices. The obtained results hold promise to be of future p...

The demand for nanocomposites of graphene and carbonaceous materials decorated with metallic nanoparticles is increasing on account of their applications in science and technology. Traditionally, the production of graphene-metal assemblies is achieved by the non-environmentally friendly reduction of metallic salts in carbonaceous suspensions. Howev...

Information security and authentication are important challenges facing society. Recent attacks by hackers on the databases of large commercial and financial companies have demonstrated that more research and development of advanced approaches are necessary to deny unauthorized access to critical data. Free space optical technology has been investi...

We show that a simple diffractive phase element (DPE) can be used to manipulate at will the positions and energy of multiple filaments generated in fused silica under femtosecond pulsed illumination. The method allows obtaining three-dimensional distributions of controlled filaments whose separations can be in the order of few micrometers. With suc...

We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no...

Single-pixel cameras allow to obtain images in a wide range of challenging scenarios, including broad regions of the electromagnetic spectrum and through scattering media. However, there still exist several drawbacks that single-pixel architectures must address, such as acquisition speed and imaging in the presence of ambient light. In this work we...

Light beams shaped by programmable megapixel spatial light modulators (SLMs) are key to broadening the applications of photonics. In this paper, we consider the application of a SLM for the generation of two mutually coherent white-light continuum optical sources by filamentation of infrared femtosecond pulses in bulk. We demonstrate that the inhom...

Graphene decorated with metallic nanoparticles (MNPs) promise to be ideal hybrid systems that can be used in optoelectronic and electronic applications, since is expected the exploitation of a combination of electronic characteristics in graphene and optical characteristics in metallic nanostructures. The design of such graphene-metal assemblies is...

Solar nanofluids are an innovative type of fluids that are able to direct harvest solar radiation. The basic idea of a solar nanofluid is to use heat transfer fluids, which usually have low absorption in the visible and near infrared range, in combination with nanoparticles. Then, a volumetric absorption within the fluid itself is promoted, which i...

Multispectral digital lensless holographic microscopy (MDLHM) operating with second-harmonic illumination is shown. Added to the improvement of the spatial resolution of the previously reported MDLHM operating with near-infrared illumination, this second-harmonic MDLHM shows promise as a tool to study the behavior of biological samples under a broa...

Raster scanning is a method which can be useful in different kinds of imaging techniques. Using simulations, we show that Fourier ptychography algorithm can improve raster scanning resolution, even using objectives with low NA.

We review different 3D imaging techniques based on microstructured illumination and single-pixel detectors. We describe also our two methods, one based on digital holography and the other on disparity maps. Preliminary experimental results are shown. Article not available.

We present a structured illumination technique to image objects hidden beneath scattering. The sample is computationally retrieved from a known ensemble of light patterns codified onto a digital micromirror device and photocurrent fluctuations provided by a detector with no spatial resolution. Results of laboratory experiments will be shown. Articl...

We introduce balanced detection in combination with simultaneous complementary illumination in a single-pixel architecture. With this novel detection scheme we are able to recover a real-time video stream in presence of ambient light.

Laser ablation in liquids by femtosecond radiation has been used to generate gold nanoparticles in a heat transfer fluid to produce a high stable thermal nanofluid as a heat transfer intensification technique. In oil based fluids, no matter the actual fabrication route, nanoparticles tend to agglomerate. Here, we report a new form to control its st...

Nowadays, one of the main challenges of nanotechnology in areas such as biomedicine, energy, sensing and catalysis is the reproducible synthesis of high-quality nanoparticles. Under this motivation, fabrication of nanoparticles by pulse laser ablation in liquids (PLAL) of a solid target has emerged. In spite of its moderate production rate and the...

During the past few years, the emergence of spatial light modulators operating at the tens of kHz has enabled new imaging modalities based on single-pixel photodetectors. The nature of single-pixel imaging enforces a reciprocal relationship between frame rate and image size. Compressive imaging methods allow images to be reconstructed from a number...

Organic heat transfer fluids are widely used in several industrial applications such as fiber manufacturing, and solar thermal power plants because they have a good thermal stability and low viscosity. Nowadays, there is an intensive research work in order to enhance the thermal properties of these fluids to improve their competitiveness in the ind...

The use of nanofluids (fluids with dispersed nanoparticles in it) is an emerging way for the enhancement of harvesting of energy in solar power plants through increasing the thermal conductivity of thermal oils. In this context, the fabrication of nanoparticles in thermal oils by chemical methods is a well-established technique. However, less atten...

In this work we have developed a single-pixel optical microscope that provides both re ection and transmission images of the sample under test by attaching a diamond pixel layout DMD to a commercial inverted microscope. Our system performs simultaneous measurements of re ection and transmission modes. Besides, in contrast with a conventional system...

One challenge that has long held the attention of scientists is that of clearly seeing objects hidden by turbid media, as smoke, fog or biological tissue, which has major implications in fields such as remote sensing or early diagnosis of diseases. Here, we combine structured incoherent illumination and bucket detection for imaging an absorbing obj...

Synthetic heat transfer fluids as thermal oils are becoming an essential tool in many applications as fiber manufacturing, concentrated solar power plants and biofuel manufacturing as they have a good thermal stability and low viscosity. However, to improve the competitiveness of these industries and reduce cost it is important to improve the therm...

One challenge that has long held the attention of scientists is that of clearly seeing objects hidden by turbid media, as smoke, fog or biological tissue, which has major implications in fields such as remote sensing or early diagnosis of diseases. Here, we combine structured incoherent illumination and bucket detection for imaging an absorbing obj...