Omar Ormachea

• PhD
• Research Director at Universidad Privada Boliviana

This article reports the construction of a portable, low-cost LIBS (Light Induced Breakdown Spectroscopy) system for use in the Bolivian mining industry for the qualitative and quantitative analysis of the composition of mineral samples. The device consists of a portable laser, a medium-resolution spectrometer and an optomechanical light collection...

We report on the design and installation of a spectrometer system for monitoring solar radiation in Cochabamba, Bolivia. Both the light intensity and the spectral distribution affect the power produced by a photovoltaic device. Local variations in the solar spectrum (especially compared to the AM1.5 standard) may have important implications for dev...

Recently, the use of smartphones has been proposed as a real option for developing measurement instruments in different areas (e.g. bio-sensors, spectroscopy, electro chemical sensor) due to their processing, visualization, connectivity and image capturing capabilities. In this work, we propose the development of a low-cost miniaturized spectromete...

The features of degenerate multi-wave mixing in resonant media (dye solutions) have been studied theoretically and experimentally. It has been demonstrated that thermal nonlinearity due to the induced absorption from the excited level contributes significantly to the efficiency of four-wave mixing, but results in lower efficiency of higher-order in...

This work presents theoretical and experimental studies of the processes of light field transformations upon frequency-nondegenerate four-wave mixing (NFWM) in a nonlinear Fabry-Perot interferometer (FPI). The principal aims are the development of a theory for intracavity four-wave mixing in complex molecular media in conditions of scattering from...

Digital transformation in education, particularly in Latin America, faces significant challenges due to the lack of standardized academic credit systems across universities. The EU-BEGP Project aims to address some of the challenges by developing a unified qualification framework that aligns with the European Credit Transfer and Accumulation System...

Digital transformation in education, particularly in Latin America, faces significant challenges due to the lack of standardized academic credit systems across universities. The EU-BEGP Project aims to address some of the challenges by developing a unified qualification framework that aligns with the European Credit Transfer and Accumulation System...

Remote Laboratories are an important tool for digital education, allowing learners worldwide to get a close to real laboratory experimental experience. There is a large body of research in online and Remote Labs, but little attention has been given to defining a service ensuring exclusive access to remote laboratory equipment. Most Remote Labs do n...

El presente modelo de utilidad consiste en un dispositivo portátil espectrométrico que comprende un mini-espectrómetro de bajo costo acoplado a la cámara de un teléfono inteligente, un kit de medición y una aplicación móvil (software) de procesamiento de datos. La cámara del teléfono inteligente captura las imágenes espectrales generadas por el min...

Instrument calibration is a critical but time-consuming process in many scientific fields. In this paper, we present an approach using recurrent neural networks (RNNs) for automatically detecting reference lines required to calibrate a spectrometer with well-known wavelengths of mercury and neon spectra. RNNs are a type of neural network that is be...

Fluorescence microscopy is an important tool for disease diagnosis, often requiring costly optical components, such as fluorescence filter cubes and high-power light sources. Due to its high cost, conventional fluorescence microscopy cannot be fully exploited in low-income settings. Smartphone-based fluorescence microscopy becomes an interesting lo...

Fluorescence microscopy is an important tool for disease diagnosis, often requiring costly optical components, such as fluorescence filter cubes and high-power light sources. Due to its high cost, conventional fluorescence microscopy cannot be fully exploited in low-income settings. Smartphone-based fluorescence microscopy becomes an interesting lo...

Book cover International Conference on Remote Engineering and Virtual Instrumentation REV 2022: Artificial Intelligence and Online Engineering pp 198–209Cite as A Low-Cost Spectrometry Remote Laboratory Alex Villazon, Omar Ormachea, Angel Zenteno & Adriana Orellana Conference paper First Online: 15 October 2022 3 Accesses Part of the Lecture No...

Laser-Induced Breakdown Spectroscopy (LIBS) is a widely used non-destructive analysis technique, which is however costly. In this paper we present the development of a low-cost 3D-printed portable LIBS system designed and built with a Technology Readiness Level 5 (TRL 5), i.e., technology validated in a relevant environment. The proposed LIBS syste...

We report the result of energetic/temporary features of a low-cost YAG:Nd ⁺⁺⁺ pulsed laser equipment based on a simmer current ionization circuit, applied to a Xe flash lamp for active media excitation.

Abstract A practical low-cost treatment system of suitable capacity was developed in order to satisfy drinking water consumption needs of people living in small rural villages affected by arsenic contamination. The system is based on a semicircular section tubular photo-reactor which has been constructed, characterized and applied to the treatment...

El agua subterránea es la principal fuente de consumo en muchos centros urbanos y áreas rurales de Bolivia, tal es el caso del Municipio de San Pedro ubicado en el departamento de Santa Cruz. El presente estudio se realizó con la Received 04 12 2021 Accepted 04 26 2020 Published 04 30 2021 Vol. 38, No.1, pp. 46-55, Ene./Abr.2021 Revista Boliviana d...

La presencia de elevadas concentraciones de arsénico encontradas en el agua de consumo de dos sitios geográficamente distantes en Bolivia, ha requerido el diseño, la construcción y la implementación de un sistema de remoción de arsénico para así obtener agua más segura para su consumo. Uno de los sitios se encuentra en una unidad educativa de la zo...

Conventional street lighting systems do not allow controlling the light intensity depending on the traffic of pedestrians or vehicles, only operate in two automatic modes (on/off) according to the availability of daylight and consume enormous amounts of electric energy. In this article, we describe the design, development and implementation of a ne...

Identifying minerals in ore concentrates require costly techniques and preparation of samples, thus limiting their instant analysis. We present the development of a low-cost portable LIBS (Laser Induced Breakdown Spectroscopy) system, to identify atomic elements in ore concentrates in-situ and in real-time. The system consists of a YAG:Nd+++ pulsed...

The epifluorescence microscopy is a powerful technique with high levels of sensibility and microscopic resolution that is applied in several areas, notably in the biomedical field. In this article, we present the design and development of a low-cost epifluorescence microscope based on laser excitation, a simplified barrier filter, and an embedded s...

The epifluorescence microscopy is a powerful technique with high levels of sensibility and microscopic resolution that is applied in several areas, notably in the biomedical field.In this article, we present the design and development of a low-cost epifluorescence microscope based on laser excitation, a simplified barrier filter, and an embedded sy...

Debido a sus capacidades de procesamiento, visualización, conectividad, y captura de imágenes, el uso de teléfonos inteligentes ha sido explorado recientemente como una opción factible para el desarrollo de instrumentos de medida en diferentes áreas (e.g. bio-sensores, espectrometría, sensores electro químicos). El presente trabajo presenta el desa...

El diagnóstico de muchas enfermedades infecciosas se realiza por métodos serológicos que evidencian indirectamente la presencia del agente infeccioso. Entre estos métodos, la Inmuno-fluorescencia Indirecta (IFI) es la menos aplicable en muchos laboratorios debido a sus exigencias en equipos y experticia. El Chagas, enfermedad ocasionada por el prot...

El siguiente trabajo presenta la implementación de una fuente de alimentación electrónica, basada en un circuito de ionización de corriente simmer, aplicado a una lámpara flash con Xe, para la excitación de un cristal del tipo YAG:Nd+++. Para el diseño y dimensionamiento de este circuito se utilizaron elementos comerciales de bajo costo. La ventaja...

Se presenta la implementación de un sistema mecánico que permite el posicionamiento angular de la rejilla de difracción de un espectrómetro óptico permitiendo ampliar su rango espectral. Se desarrollaron los circuitos electrónicos para un micro-servomotor controlado por un microcontrolador. Este microcontrolador PIC interacciona con un módulo bluet...

This work introduces the implementation of a simmer current circuit applied to aXe flash lamps, for excitation of a YAG: Nd+++ crystal type. Low-cost commercial elements were used for designing and dimensioning of this circuit. The advantage of using the simmer circuit involves the application of high voltage (about 20 kV) only once, to ionize the...

Se presenta el desarrollo de un prototipo de comunicación inalámbrica de señales mediante el uso del espectro de luz visible con un ancho de banda de 5 MHz (aproximadamente 80 Mbps) y una distancia de 15 cm, el sistema desarrollado permite la transmisión de señales de audio & video de forma inalámbrica mediante un LED (luz blanca). La luz que emite...

Se ha realizado un relevamiento de la calidad físico-química y presencia de arsénico en aguas de pozos con profundidad mayor a 50 m, ubicados en la zona periurbana oeste de la ciudad de Cochabamba, mediante muestreos llevados a cabo durante dos periodos diferentes (húmedo y seco). Por otra parte, se ejecutó un estudio de desempeño de una planta pil...

Se presenta el desarrollo de un sistema de control inalámbrico, basado en tecnología bluetooth, para un sistema LIBS (Laser-Induced Breakdown Spectroscopy) que utiliza un prototipo láser Nd:YAG+++ portátil de una potencia estimada de 10 MW/cm2, un espectrómetro de difracción de 0.27 nm de resolución y 76.9 nm de ancho espectral (prototipos construi...

The arsenic concentrations and quality of water from 18 deep water wells (above 50 m) located in the west side peri-urban area of Cochabamba, Bolivia have been assessed, together with a study on the performance of a low cost solar collector based pilot plant applied to arsenic removal. The analyzed water samples indicated a calcium-bicarbonate (Ca-...

We describe the development of a Bluetooth-based wireless control for a LIBS (Laser-induced Breakdown Spectroscopy) system that uses a portable prototype Nd:YAG+++ laser with an estimated power of 10MW/cm2, a spectrometer with 0.27nm of diffraction resolution and 76.9nm of spectral width. All the prototypes were developed and built in our research...

Se presenta el desarrollo de un sistema de análisis fisicoquímico basado en espectroscopia de emisión atómica inducida por radiación láser, o LIBS por sus siglas en ingles. Se desarrolló el sistema LIBS compuesto de un láser Nd:YAG +++ portátil de una potencia estimada de 10 MW/cm2, un espectrómetro de difracción de 0.27 nm de resolución y 76.9 nm...

Se desarrolló un espectrómetro de difracción con elementos comerciales de bajo costo. Se diseñó con la configuración de un espectrómetro con rejilla de difracción por transmisión y entrada de luz regulable. Se construyó con elementos comerciales y de descarte como una rejilla de difracción holográfica, lente colimadora y objetivo de proyector digit...

Se diseñó y construyó un prototipo funcional de un sistema de medición de radiación solar (global y difusa) basado en un espectrómetro de amplio espectro (UVA, VIS y parte del IR cercano) para el monitoreo solar en Cochabamba, Bolivia, conjuntamente con un sistema similar instalado en Ontario, Canadá. Los datos obtenidos en dos regiones con caracte...

El presente trabajo de investigación tiene por objeto el estudio del efecto de pulverizar agua sobre la superficie de un panel fotovoltaico convencional en funcionamiento, mediante un atomizador para controlar la temperatura y mantenerla constante. Se realizaron medidas de potencia en circuito abierto de un panel de 55 Wp de la marca ZYTECH manteni...

Se ha construido y caracterizado un foto-reactor tubular de sección circular que ha sido aplicado al tratamiento de aguas subterráneas contaminadas con As(V), utilizando las técnica de la Remoción de Arsénico por Oxidación Solar (RAOS). El concentrador solar fue construido reciclando materiales desechados: tubos de vidrio proveniente de lámparas fl...

El presente trabajo de investigación, consiste en el diseño y construcción de un sistema de concentración de energía solar térmica, mediante colectores de geometría circular de bajo costo, para el calentamiento de agua, el líquido calentado es utilizado como elemento termo-regulador para la calefacción de ambientes en nuestra institución académica....

A semicircular section tubular photoreactor has been constructed, characterized and applied to the treatment of groundwater contaminated with As(V) by means of the SORAS (solar oxidation and removal of arsenic) technique, using ferrous and citrate salts. The solar concentrator was built with recyclable waste materials: glass tubes from fluorescent...

Se presenta el diseño y construcción de un espectrómetro óptico para su uso en sistemas LIBS (Laser Induced Breakdown Spectroscopy), basado en una rejilla de difracción por reflexión y elementos ópticos comerciales. Se usaron objetivos fotográficos de 50 mm f 1.4 y 135 mm f 2.8 como lente de colimación y objetivo de cámara, respectivamente. También...

Dissolved arsenic (As) concentration in drinking water collected during rainy season from drilled wells in Cochabamba, Bolivia showed a range from <3.0 to 153 µg/L and averaged 30.0 µg/L, while As concentrations collected during dry season ranged from <3.0 µg/L to 581 µg/L and averaged 168.3 µg/L, showing a wide variation in the distribution betwee...

El presente trabajo de investigación, consiste en el diseño y construcción de un sistema de concentración de energía solar térmica, mediante colectores de geometría circular de bajo costo, para el calentamiento de agua, el líquido calentado es utilizado como elemento termo-regulador para la calefacción de ambientes en nuestra institución académica....

La eficiencia cuántica de materiales fotovoltaicos depende de la longitud de onda de la radiación incidente, el espectro solar influye en la producción de energía producida por estos sistemas. En el presente trabajo, se diseñó y construyó un prototipo funcional de un sistema de medición de radiación solar (global y difusa) basado en un espectrómetr...

RESUMEN Se han construido y caracterizado cuatro foto-reactores tubulares de sección semi-circular, y se aplicaron al tratamiento de aguas subterráneas contaminadas con As(V), utilizando las técnica de la Remoción de Arsénico por Oxidación Solar (RAOS). Los concentradores solares fueron construidos reciclando materiales desechados: tubos de vidrio...

En el presente trabajo de investigación se realizó el diseño y construcción de un láser portátil y pulsado del tipo YAG:Nd+++ para aplicaciones LIBS. La fuente de alimentación del sistema está basada por un bloque de potencia formado por un circuito triplicador de voltaje y 6 capacitores de 330 uF/ 200 V cada uno, este funciona con 4 baterías recar...

RESUMEN En el presente artículo se presenta los avances en la construcción de un sistema LIDAR monostático coaxial para el estudio de las partículas contaminantes existentes en la capa troposférica sobre la ciudad de Cochabamba – Bolivia y que son producto de la actividad agraria en regiones aledañas, muy intensas principalmente en época seca de po...

En el presente trabajo de investigacion se realizo el diseno y construccion de una fuente de alta tension para la excitacion de emision coherente de alta intensidad en el diapason UV en medios gaseosos. El transformador principal fue disenado con los siguientes parametros P=660W, voltaje en el primario U=220 V y en el secundario U=2200 V, se utiliz...

Se ha construido y caracterizado un foto-reactor tubular de sección circular para su aplicación al tratamiento de aguas subterráneas contaminadas con Arsénico, As(V), utilizando las técnica de la Remoción de Arsénico por Oxidación Solar (RAOS). El concentrador solar que posee una capacidad de radiación equivalente a 2,8 soles, fue construido recicl...

Se diseno y construyo un prototipo funcional de un sistema fotovoltaico (SFV) con el objetivo principal de incrementar la eficiencia de sistemas fotovoltaicos convencionales. Este nuevo sistema implementa elementos de optica y utiliza sistemas de seleccion de longitud de onda que permiten un uso efectivo del espectro electromagnetico solar. Se obtu...

Resumen The schemes for recording and reading of dynamic holograms in conditions of nondegenerate four- and six-wave mixing in a nonlinear Fabry-Perot interferometer have been analyzed theoretically. It has been demonstrated that there is a possibility for a considerable improvement in the diffraction efficiency and angular selectivity of dynamic...

Se diseñó y construyó un láser (prototipo funcional) sólido pulsado del tipo YAG:Nd+++ excitado ópticamente por una lámpara flash (medio gaseoso = Xenón), con picos intensos de emisión en longitudes de onda cercanas a las bandas de absorción de los iones de Nd+++. La longitud de onda de generación fundamental corresponde al infrarrojo λ=1.064 µm, a...

The use of optical techniques in medical praxis allows practitioners to improve their tools. This improvement is realized in two main aspects, treatment and characterization of biological tissue. The former deals with methods like Photodynamic Therapy (PDT), Low Intensity Laser Therapy (LILT) or Hyperthermia. Tissue characterization by optical mean...

Among the frequency conversion methods for three-dimensional images characterized by a complex wave front, of particular interest are those based on nonlinear dynamic hologram recording. The use of resonant media including the solutions of complex organic compounds looks promising for realization of the process over wide temporal and spectral range...

Nowadays, all optical devices based on nonlinear effects acquire a great importance in optical communications systems and photonic processing. Particularly relevant are the devices that use low-level power pumping in the generation of those effects. These optical devices can be implemented by means of different structures and materials. One of the...

The recording of dynamic holograms during multiwave interactions in clear organic fluids (ethanol, acetone, dioxan, etc.) is investigated. It is shown that the fifth-order nonlinearities and higher become activated along with the cubical nonlinearity under the intense laser excitation (∼100 MW cm−2) in the near-IR spectral range, which allows visua...

Se diseñó y construyó un láser sólido pulsado del tipo YAG:Nd+++ excitado ópti­camente por una lámpara flash (medio gaseoso = Xenón), con picos intensos de emisión en longitudes de onda cercanas a las bandas de absorción de los iones de Nd+++. La longitud de onda de generación corresponde al infrarrojo A = 1,064pm, armónica prin­cipal, con la posib...

The field of biomedical optics is promising in medical praxis. The study of laser thermal treatment and polarization-based characterization of tissue under it can be utilized in the correction of certain disorders with good results.

Способ записи динамической голограммы с увеличенной дифракционной эффективностью, включающий воздействие на выполненную в виде плоскопараллельного слоя светочувствительную резонансную среду когерентными между собой опорным и объектным световыми пучками с частотой, обеспечивающей переход молекул резонансной среды в возбужденное состояние, и одноврем...

The schemes of degenerate and nondegenerate multiwave mixing in saturable absorbers (Rhodamine 6G and polymethine 3274 U dyes) exhibiting higher-order nonlinearities have been analyzed experimentally. The role of polarization gratings resultant from spatial modulation of the light field polarization state at the orthogonal polarization of the holog...

The schemes for nonlinear recording of dynamic holograms in multilevel resonant media, in conditions when the fifth-and higher-order nonlinearities are exhibited, have been studied both theoretically and experimentally. The optical methods to control the diffraction efficiency of nonlinear dynamic holograms with the use of an additional light beam...

The results of theoretical and experimental investigations into degenerate and non-degenerate four-wave mixing in Fabry-Perot microresonator with dye solution as a nonlinear medium are presented. It is shown that the efficiency of holographic methods for wave-front and frequency conversion may be considerably increased due to the use of recording o...

This work presents experimental studies into the energy efficiency of multiwave mixing in complex molecular media exhibiting higher order nonlinearities in two cases: volume holograms in the standard geometry of degenerate four-wave mixing and self-diffraction of the recording waves from thin dynamic gratings. The use of different combinations of m...

Advances in the development of nonlinear interference and holographic systems based on four-wave mixing point to great potentialities of these systems for real-time processing and correction of the light fields, formation of the desired space-time structures of laser radiation, image transfer, realization of logic and mathematical operations, creat...

Measurement of liquid level in tanks is an important function in many industrial processes. Optical-fiber sensors have high sensitivity and its non-electrical nature and immunity to electromagnetic interference make them safe for applications in explosive environments and oil tanks. In this work we present a liquid-level sensor system based on lase...

The results of theoretical and experimental investigations into four-wave mixing in microresonators with resonant and thermal nonlinearities are presented. Theoretical models of dynamically-induced optical gratings have been derived in two cases of the light beams interaction: when a nonlinear medium is incorporated into Fabry-Perot interferometer...

One of the main advances of dynamical holography is the possibility to operate with coherent images in real-time experimental situation. Non-degenerate four-wave mixing has some advantages among different holographic methods because it gives the possibility to perform visualization of infra-red images or to convert visible radiation into ultra-viol...

For the purpose of determining the higher-order nonlinear optical susceptibility the diffraction method based on investigation into the Fourier-expansion spatial components for the anharmonic grating of the refractive index has been used. Comparison between the experimental and theoretical data makes it possible to relate unambiguously the energy e...

In this work the different schemes of propagation and interaction of the light beams in nonlinear Fabry-Perot interferometer have been studied theoretically and experimentally. Degenerate and non-degenerate four-wave mixing have been realized in the cavity of Fabry-Perot type using Rhodamine-6G dye and polymethine dye 3274U solution as saturable ab...

This work presents theoretical and experimental studies of the energy efficiency of multiwave mixing in complex molecular media (dye solutions) exhibiting higher order nonlinearities. There is a great variety of such media, including the resonance ones revealing nonlinearities of higher orders due to the absorption saturation effect and transitions...

The importance of nonlinear optical devices is increasing due to their hopeful characteristics such as small size, high speed or even low power consumption. These devices integrated in all-optical systems achieve the best results because of the elimination of optoelectronic or electro optic conversions that imply great reductions in these advantage...

Schemes of polarization holographic recording at multiwave mixing in dye solutions were analyzed. The method of self-amplification of polarization gratings under lasing conditions in a cell with dye was proposed. It was found that polarization of a diffracted wave depends on the diffraction order and can coincide with polarization of a signal wave...

Проанализированы схемы поляризационной голографической записи при многоволновых взаимодействиях в растворах красителей. Предложен метод самоусиления поляризационных решеток при реализации в кювете с красителем режима лазерной генерации. Установлено, что поляризация дифрагированной волны зависит от порядка дифракции и может совпадать с поляризацией...

In this work a theoretical study of the interaction between a light beam and an anisotropic nonlinear interferometer has been considered and methods to control the transmission of the microcavity using optical and magnetic fields have been developed. It has been demonstrated that anisotrophy of intracavity media determines the differences in transm...

In the present work consideration is given to theoretical and experimental analysis of the possibilities for improving the efficiency of multiwave mixing in the process of dynamic hologram recording in solutions of complex organic compounds with additional irradiation of resonant medium at a frequency falling within the absorption band from the exc...

The potentialities of diffraction methods for wavefront transformations may be considerably widened due to the use of nonlinear recording of dynamic holograms enabling multiwave mixing in media with the fifth and higher order nonlinearities. There is a great variety of such media including the resonant ones for which the presence of higher order no...

The mechanism of multiwave mixing realized in solutions of complex organic compounds (dyes), in conditions when higher-order nonlinearities are exhibited along with the cubic one, has been analyzed theoretically and tested experimentally. Nonlinear recording of dynamic holograms enables significant improvement of the potentialities of holographic m...

The features of the implementation of multiwave interactions in complex molecular media were investigated. Multiwave interactions were realized in an ethanol solution of rhodamine 6G dye and in a toluene solution of C60 fullerene. Theoretical and computer models were used to investigate the dependence of diffraction efficiency on the intensity of t...

The schemes of light beam transformations by volume dynamic holograms in resonant media revealing the fifth-or higher-order nonlinearities have been theoretically analyzed. N-wave mixing has been realized by changing of the propagation direction or frequency of the read-out wave in the solution of Rhodamine 6G and polymethine 3274U dyes. It has bee...