Thick PQ:PMMA transmission holograms for free-space optical communication via wavelength-division multiplexing

Gamboa, Julian; Hamidfar, Tabassom; Vonckx, Joseph; Fouda, Mohamed; Shahriar, Selim M.

doi:10.1364/ao.434503

Cited by 10 publications

(7 citation statements)

References 21 publications

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“…Volume HOEs are a great candidate for such an application, as they can function as diffractive spectral filters with customizable center wavelength and FWHM. 8,11 PQ:PMMA is a write-once read-many photopolymer that can be created in thicknesses up to millimeter scale, allowing the stored holograms to function in the Bragg regime. Gratings are formed by interfering expanded laser beams within the material, whereby the peaks and troughs of the interference pattern result in correspondingly strong or weak reactions between the PQ dye molecules and MMA monomers, yielding a modulation of the refractive index.…”

Section: Nir Holographic Filtersmentioning

confidence: 99%

“…In order to overcome this limitation, it is necessary to perform k-vector matching to find the writing angles for 532 nm beams that produce equivalent gratings that can match the design parameters. 8,11 Figure 2. Spectral-spatial filtering diagram.…”

Section: Nir Holographic Filtersmentioning

confidence: 99%

“…This holographic polymer substrate can produce volume HOEs with millimeter-scale thicknesses that allow for the multiplexing of multiple gratings designed for arbitrary Bragg wavelengths and Bragg angles. [7][8][9] *JulianGamboa2023@u.northwestern.edu; phone +1 (847) 491-7064; lapt.ece.northwestern.edu…”

Section: Introductionmentioning

confidence: 99%

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Monocular passive ranging through a PQ:PMMA holographic wavelength division demultiplexer

Gamboa¹,

Hamidfar²,

Shen³

et al. 2023

Practical Holography XXXVII: Displays, Materials, and Applications

Self Cite

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Distance estimation is an important yet challenging part of any tracking system, as being able to quickly locate an object in 3D space allows for the automated targeting of communication, delivery, and interception systems, as well as providing important telemetry about fast moving objects. A monocular passive ranging system is defined as that which only requires one observation point through which it measures some outside signal to estimate range. The approach presented here simultaneously observes the intensity of light emitted by the target at three wavelength bands with ~10nm FWHM, centered at 750, 762, and 780 nm. The light is separated using a PQ:PMMA holographic optical element (HOE) configured as a wavelength division demultiplexer. Light at the two outer bands experiences negligible absorption in the atmosphere, while light at ~762 nm is strongly absorbed by O2. By comparing the intensity of the two unabsorbed bands, we may interpolate the expected intensity of the 762 nm band if there is no O2 in the path. This is then used in conjunction with the 762 nm band measurement to approximate the total O2 transmissivity. Finally, Beer’s law and the HITRAN database provide us with the tools to convert a transmissivity into a distance estimation. The use of an HOE is pivotal in the practicality of such a system, as it allows us to measure all three signals simultaneously, thus eliminating the effects of turbulence and reducing overall noise.

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Section: Nir Holographic Filtersmentioning

confidence: 99%

Section: Nir Holographic Filtersmentioning

confidence: 99%

See 1 more Smart Citation

Monocular passive ranging through a PQ:PMMA holographic wavelength division demultiplexer

Gamboa¹,

Hamidfar²,

Shen³

et al. 2023

Practical Holography XXXVII: Displays, Materials, and Applications

Self Cite

View full text Add to dashboard Cite

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“…Looking for new high-performance storage materials is an effective way to improve the holographic storage properties. Among different holographic storage media, PQ/PMMA polymers [ 11 ] exhibit unique holographic properties with high storage density, a simple fabrication method, negligible shrinkage and controllable size [ 12 , 13 , 14 ]. However, the response time of this material, which is approximately tens of seconds, has not been effectively improved.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Investigations of Diffraction Characteristics Influenced by Holographic Reciprocity Effect in PQ/PMMA Polymers

Liu

Sun

2023

Polymers

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We propose the holographic reciprocity effect (HRE) to describe the relationship between the exposure duration (ED) and the growth rate of diffraction efficiency (GRoDE) in volume holographic storage. The HRE process is investigated experimentally and theoretically in order to avoid the diffraction attenuation. Herein, introducing the medium absorption, we present a comprehensive probabilistic model to describe the HRE. PQ/PMMA polymers are fabricated and investigated to reveal the influence of HRE on the diffraction characteristics through two recording approaches: pulsed exposure with nanosecond (ns) level and continuous wave (CW) exposure at the millisecond (ms) level. We obtain the holographic reciprocity matching (HRM) range of ED in PQ/PMMA polymers with 10−6~102 s level and improve the response time to microsecond (μs) order with no diffraction deficiency. This work can promote the application of volume holographic storage in high-speed transient information accessing technology.

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“…Volume holograms have been the focus of many research endeavors for many decades. These holographic optical elements (HOEs) are often easily customizable and can achieve high diffraction efficiencies (DEs), making them a practical choice for optical processing and storage devices such as memory discs, 1,2 spectral filters, 3 or lenses. [4][5][6] Due to the thickness of these devices, the gratings fall into the Bragg regime.…”

Section: Introductionmentioning

confidence: 99%

Holographic diffraction of complex beams and gratings: theory and simulation

Shen¹,

Gamboa²,

Hamidfar³

et al. 2023

Practical Holography XXXVII: Displays, Materials, and Applications

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Volume holographic optical elements (HOEs) are of great interest for dense information storage and optical processing such as wavelength division multiplexing (WDM) and angle multiplexing. There are numerous theoretical frameworks that attempt to model and test diffraction from a holographic grating, among the most prominent of which is Kogelnik’s coupled-wave theory, which applies to thick holograms. However, diffraction from grating geometries resulting from interference among more than two wave-vectors is difficult to model mathematically. In particular, gratings formed from converging or diverging beams present curved profiles that vary with the position inside the material. One approach to analyze these types of holographic gratings is to use a finite element method (FEM) to search for a steady-state solution for the wave equation of a beam propagating through, and diffracting from, the grating. Such a method will necessarily be computationally intensive given that the simulation will require a resolution smaller than the reading wavelength but will encompass a large volume, as is required for a thick hologram. Current technology has enabled this approach to be a viable alternative to traditional modeling. Here, we present the results of an FEM analysis using the COMSOL Multiphysics 6.0 computer program to simulate the diffraction of holographic gratings with non-trivial profiles. The results enable us to more accurately design volume HOEs with non-planar profiles such as lenses, WDM, etc., to achieve better Bragg selectivity and overall higher performance.

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Thick PQ:PMMA transmission holograms for free-space optical communication via wavelength-division multiplexing

Cited by 10 publications

References 21 publications

Monocular passive ranging through a PQ:PMMA holographic wavelength division demultiplexer

Monocular passive ranging through a PQ:PMMA holographic wavelength division demultiplexer

Theoretical and Experimental Investigations of Diffraction Characteristics Influenced by Holographic Reciprocity Effect in PQ/PMMA Polymers

Holographic diffraction of complex beams and gratings: theory and simulation

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