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New paper in Optics Letters about a new technique of measuring the LCOS backplane deformation


INT1A new paper is available in Optics Letters entitled Measuring the spatial deformation of a liquid-crystal on silicon display with a self-interference effect.

Here we present a simple technique to characterize the spatial non-uniformity of a LCOS-SLM, based on illuminating the display with a wavelength out of the operation range. In this situation there is a significant reflection at the output surface and a Gires–Tournois type interferometer is directly created, without any alignment requirement and insensitive to vibrations. The beam reflected at the output surface is the reference beam, while the beam reflected at the silicon backplane is modulated with the addressed gray level in order to quantitatively derive its deformation. We provide an experimental demonstration using a LCOS-SLM designed to operate in the near-infrared range but illuminated with visible light.

This work is part of the PhD Thesis of David Marco and has been done in collaboration with our colleague Prof. Asticio Vargas, from Universidad de La Frontera, Temuco, Chile.


Viernes, 7 de agosto de 2020 Sin comentarios

New paper in OSA Continuum about double ring interference with binary axicons


CbeltA new paper is available at OSA Continuum entitled Double-ring interference of binary diffractive axicons.

Here we report on the interference between the double rings generated by the Fourier transform of a binary diffractive axicon. These two rings have the same size and correspond to the +1 and -1 diffracted order beams. The interference condition between both rings can be easily changed by adding a constant phase bias. Additionally, this interference condition can be changed along the ring.

This work has been done in collaboration with our colleagues at San Diego State University Prof. Jeffrey A. Davis, Prof. Don M. Cottrell and Benjamin Gutierrez.


Lunes, 15 de junio de 2020 Sin comentarios

Open PhD student position available at TecnOPTO


We are looking for a MSc, preferably with experience in experimental optics and photonics, to develop a PhD Thesis in the field of optical polarimetry within a grant from the Valencian Government, Santiago Grisolía Program, ref. GRISOLIAP/2020/004.

Required conditions
– The candidate must hold a MSc degree in Physics, Electrical Engineering, Optics or related degree from a non-Spanish institution.
– The degree must have finished after January 1st 2016 and must qualify to enter a PhD program.
– Candidates must not hold a previous PhD degree (the selected candidate will have to enroll a UMH Doctorate Program when starting the contract.
– English language OR Spanish (Spanish language is NOT required).

Recommended experience:
– Work experience in experimental and instrumental optics.
– Computational skills (Matlab, C++ , Labview…)
– Fluent English written and spoken.

Job conditions:
– Period: Three years (renewable every year)
– Starting date: October 1st 2020
– Annual gross salary of 22,192.80 euros, plus 1,600 euros to cover travel expenses.
– Social security and institutional benefits included.

Interested candidates should submit their application by email before June 23, 2020, including a CV, the contact of two persons who can provide a recommendation letter, and one motivation letter stating the candidate’s interest in the project. Contact: i.moreno@umh.es


Lunes, 15 de junio de 2020 Sin comentarios

New paper in Applied Sciences about the generation of hybrid vector beams with a detuned q-plate


ASOur new paper is available in Applied Sciences, entitled Analysis of hybrid vector beams generated with a detuned q-plate. This article belongs to the journal special issue devoted to Ultrafast Vortex Pulses.

We use a tunable commercial liquid-crystal q-plate tuned to a quarter-wave retardance to study the generation and dynamics of different types of hybrid vector beams. Standard hybrid vector beams but also petal-like hybrid vector beams are generated. These beams are analyzed in the near field and compared with the far field distribution, where their hybrid nature is observed as a transformation of the intensity and polarization patterns.

The work has been developed during the stay in Elche last year of Julio César Quiceno, from Universidad del Valle, in Cali, Colombia.


Viernes, 15 de mayo de 2020 Sin comentarios

New paper in OSA Continuum showing Bessel beams with tunable control through maximum phase modulation


getThumbnail.cfmOur new publication is available in OSA Continuum Dynamic control of Bessel beams through high-phase diffractive axicon.

We present the realization of a high-phase diffractive axicon using a an SLM that exhibits 10π phase modulation. We compare the results with standard diffractive axicons with only 2π phase modulation. We show that high-phase modulation axicons generate Bessel beams with a shorter range and a smaller radius than standard axicons with the same period. We also find that the higher phase modulation regime provides improved diffraction efficiency since fringing effects are reduced. Dynamic control of Bessel beams is presented, controlled through the phase modulation dynamic range.

The paper has been done in collaboration with our friends at San Diego State University.


Categories: International, Projects, Research Tags:

Martes, 12 de mayo de 2020 Sin comentarios

TecnOPTO organizes a workshop on ‘Structured Light, Polarimetry and Imaging’


Workshop

On November 25th, 2019 we organized a workshop entitled ‘Structured Light, Polarimetry and Imaging‘.

The workshop was held at the Institute of Bioengineering of UMH, and we could count with the participation of experts from different groups in Spain working in these related fields. The program can be viewed at the following link.

We thank all the participants and attendees to this extremely interesting and motivating reunion.


Martes, 26 de noviembre de 2019 Sin comentarios

New paper in OLEN analyzing the diffraction efficiency of stepped gratings in large phase modulation SLMs


OLENOur new publication is available in Optics & Lasers in Engineering, entitled Diffraction efficiency of stepped gratings using high phase-modulation spatial light modulators.

We study the diffraction efficiency of linear phase (blazed) diffraction gratings displayed onto SLMs that exhibit a large phase modulation range, reaching a maximum phase modulation of 8pi or 10pi radians. We analyse these effects for their important implications in the Nyquist limit for diffractive elements

The paper has been done in collaboration with our friends at San Diego State University.


Domingo, 3 de noviembre de 2019 Sin comentarios

Special Section in Optical Engineering about Spatial Light Modulators


A special section on Spatial Light Modulators (SLMs) – Devices and Applications will be published in the journal Optical Engineering. Ignacio Moreno and María Del Mar Sanchez-Lopez are Guest Editors of this special section of the journal, together with Prof. Andrew Forbes and Prof. Yoshio Hayasaky.

The following link leads to the journal Call for Papers.

The deadline for submitting papers is October 15th, 2019. See here the flyer of the OE special section on SLMs. OE-SLMs

 


Miércoles, 14 de agosto de 2019 Sin comentarios

David Marco and Julio César Quiceno present their results at IONS 2019, Barcelona, June 2019


In his talk entitled «Two-dimensional geometric phase vortex grating based on the optimal triplicator design», David presented the design and characterization of a liquid-crystal geometric phase diffraction grating that generates 3×3 diffraction orders with vortex beams of different topological charges, and showed the operation of this grating as a vortex detector. These results have recently been published in Optics Express: link to the paper.

Julio César presented a poster entitled “Hybrid vector beams generated by cascaded q-plates” where he demonstrated a q-plate-based optical system capable of generating a variety of hybrid vector beams, and showed the rotation of their polarization pattern when comparing the near field and the far field captures. This optical system is more compact than those based on SLMs whilst bearing a notable degree of versatility.

They have enjoyed the interesting conferences, scientific discussions and networking opportunities of this conference hosted by the OSA student chapter at ICFO and backed by the International OSA Network of Students. Link to the conference.

IONS

 

 


Domingo, 7 de julio de 2019 Sin comentarios

New paper in Optics Letters on breaking the Nyquist limit for diffractive lenses with high phase modulation displays


OL FIGWe published a new paper in Optics Letters entitled Encoding lenses with focal lengths lower than the Nyquist limit using high phase-modulation displays. In this work we show that focal lengths much lower than the classical Nyquist limit can be encoded onto spatial light modulators having a large phase-dynamic range.

Experimental results are included with a display showing 10π phase modulation reducing the Nyquist limit by a factor of about 1/10. We used a  Hamamatsu reflective LCoS device designed for use in the near infra-red (NIR) range, but operated with visible light in order to achieve such large modulation regimes.

The work has been done in collaboration with our friends at the Department of Physics of San Diego State University.


Jueves, 27 de junio de 2019 Sin comentarios