&lt;title&gt;Holographic PDLC for photonic applications&lt;/title&gt;

Domash, Lawrence H.; Crawford, Gregory P.; Ashmead, Allan C.; Smith, Ronald T.; Popovich, Milan M.; Storey, John M. D.

doi:10.1117/12.405328

Cited by 50 publications

(21 citation statements)

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“…There have been numerous approaches to manipulate and improve HPDLC performance parameters such as diffraction efficiency, contrast, switching speed and voltages. These include photocurable acrylate systems (1,3,6,12,(14)(15)(16)(17)(18), photopolymerisable thiol-ene based polymers (9)(10)(11)(19)(20), non-reactive surfactant-like molecules (21)(22)(23), conductive polymer molecules (8,24), and so on (25)(26)(27)(28). In most visibly recorded HPDLCs to date, a number of additives are typically required (23).…”

Section: Introductionmentioning

confidence: 99%

Transmission holographic polymer‐dispersed liquid crystal based on fluorinated polymer matrices

Woo¹,

Kim²

2008

Liquid Crystals

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The grating formation dynamics, morphology and electro-optical properties of transmission gratings of holographic polymer dispersed liquid crystals (HPDLCs) were investigated based on partial fluorination of the host polymer matrices by incorporating three different types of fluorinated monomer. Addition and increasing amounts of fluorinated monomer gave short saturation time and increased off-state diffraction efficiency with a maximum due to the chemical incompatibility between fluorinated compounds and LC, whereas the droplet size increased with increasing fluorinated monomer content. In addition, fluorinated monomer induced decreased switching voltage and increased response time due to the low anchoring energy at the polymer-LC interfaces and increased droplet size. At an optimum content of fluorinated monomer, a minimum switching voltage of 5 V mm 21 , a rise time of 0.25 ms and a decay time of 23.15 ms were obtained.

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Section: Introductionmentioning

confidence: 99%

Transmission holographic polymer‐dispersed liquid crystal based on fluorinated polymer matrices

Woo¹,

Kim²

2008

Liquid Crystals

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“…Several groups have worked for a number of years using holographic photopolymerization to template the phase separation of the LC domains. [2][3][4][5][6][7] The propensity of phase separation in mixtures of high-molecular weight polymers and low molar mass liquid crystals in sufficient concentration combined with the spatial and temporal anisotropy of holographic photopolymerization process results in the periodic phase separation of nanoscale-sized liquid crystal domains. Nanosized LC domains are spatially separated by crosslinked polymer regions on a periodicity defined by the holography process.…”

Section: Introductionmentioning

confidence: 99%

Effect of gel-point versus conversion on the real-time dynamics of holographic polymer-dispersed liquid crystal (HPDLC) formation

Bunning

Natarajan

Tondiglia

et al. 2003

Liquid Crystals VII

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We present data that indicates much more uniform reflection grating notches are formed when using thiol-ene photopolymerization as compared to the typical multifunctional acrylate photopolymerization. The scaling behavior of both diffraction efficiency and notch bandwidth versus thickness is presented for both acrylate and thiol-ene-based polymer hosts. The latter follows predicted behavior over a much larger range of thickness than the former. We attribute these differences to a delay in the gel-point with respect to the reaction start. Since the bulk of shrinkage occurs before gelation, detrimental effects caused by anisotropic stress build-up and subsequent relaxation is minimized. Using real-time monitoring techniques, we monitor the blue shift of the notch wavelength and the bandwidth development as a function of time for both chemistries. We demonstrate that thicker samples with appreciable diffraction efficiency and narrow bandwidths can be obtained.

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“…Others have used reflective gratings where the grating fringe planes are parallel to the substrates. Some of the applications, such as color filters and beam steering devices, are wavelength specific and can be used to isolate and manipulate individual wavelengths oflight [6][7]. For others such as the electrically variable optical attenuator (EVOA), the grating pitch has been set to be offresonance, and the HPDLC material can be used to electrically tune the bulk refractive index of a particular portion of device.…”

Section: Introductionmentioning

confidence: 99%

“…Comparison of major parameters of approaches[7, 9] Digilens' approach, HPDLC-based electrically switchable gratings, offers solid-state, high speed, low cost solutions for photonics components. Building on the advantages of ESBG technology, Digilens is developing a family of optical telecommunication devices -DigiWaveTM technology -to meet the rapidly growing demands of the…”

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confidence: 99%

Organic-based electrically switchable Bragg gratings and their applications in photonics and telecommunications

et al. 2001

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An organic electrically switchable holographic material and its applications to display and photonics components are outlined. This material is an extension ofpolymer dispersed liquid crystal (PDLC) technology. Consisting of liquid crystal (LC), prepolymer and photoinitiator, a holographic PDLC (HPDLC) mixture can form LC droplets in the polymer matrix 1-2 orders ofmagnitude smaller than those in regular PDLCs. Thin HPDLC films sandwiched between transparent electrodes such as ITO-coated glass can be used to record high-resolution holographic gratings. These gratings, the result of the index modulation due to the phase separation of the LC from the polymer matrix, can be easily switched on and off under an electric voltage at a high speed 1 -2 orders of magnitude faster than that of a regular PDLC device or a bulk nematic/cholesteric LC based device. Two types of switchable diffractive gratings, transmissive and reflective gratings, will be discussed. Applications such as wearable displays, portable projectors and optical networking components will be described in the presentation. Prototypes of some of these devices will be demonstrated in the presentation.

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<title>Holographic PDLC for photonic applications</title>

Cited by 50 publications

References 0 publications

Transmission holographic polymer‐dispersed liquid crystal based on fluorinated polymer matrices

Transmission holographic polymer‐dispersed liquid crystal based on fluorinated polymer matrices

Effect of gel-point versus conversion on the real-time dynamics of holographic polymer-dispersed liquid crystal (HPDLC) formation

Organic-based electrically switchable Bragg gratings and their applications in photonics and telecommunications

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