Thermally tunable polymer microlenses

Huang, Xian; Cheng, Chao‐Min; Wang, Li; Wang, Bin; Su, C. W.; Ho, Mon-Shu; LeDuc, Philip R.; Lin, Qiao

doi:10.1063/1.2945646

Cited by 23 publications

(14 citation statements)

References 15 publications

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“…An interferometric technique has been used before for the optical testing of the micro-lenses but exclusively for measuring the profile of the solid micro-lenses rather than for checking directly the wavefront characteristics [23,24]. Besides, the usual testing procedure reported for tunable liquid micro-lenses consists of relatively simple imaging experiments or focal spot analysis [21,22,26]. The optical testing of the micro-lenses was performed by using an interferometric system based on digital holography (DH), under a microscope configuration.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, special liquid-based optics, such as axicon lenses, have been developed by using polymeric materials as liquid containers [19]. Cylindrical lenses with hydrodynamic tunability [20] and polymer lenses tuned thermally [21] have been also investigated and tested. The EW manipulation of liquids has been also reported for angle tilting of suspended micro mirrors or gratings [14], for the realization of beam-steering devices [15] and displays [16].…”

Section: Introductionmentioning

confidence: 99%

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Tuneable liquid microlenses onto a functionalized polar dielectric substrates: formation and characterization

et al. 2010

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Liquid lenses are becoming important optical devices for a wide range of applications, from mobile-phone cameras to biological imaging modalities. Their biggest advantage is their potential to have a variable focus that can be changed to obtain a different radius of curvature and thus optical power. The tunability of such micro-lenses could be of great interest to the field of micro-optics thanks to the possibility to achieve focus tuning without moving parts and thus favouring the miniaturization of the optical systems. A special class of tunable liquid micro-lenses is presented here. They are generated by electro-wetting effect under an electrode-less configuration. The lensing effect is induced by the pyroelectric effect on polar dielectric crystals we named pyroelectric-electrodeless-electro-wetting (PEEW). If a thin liquid film is spin coated on a z-cut lithium niobate wafer, the pyroelectric effect causes surface-charges at the liquidsolid interface when the substrate suffers temperature changes. Electric charges build up on the substrate's surface by pyroelectricity and are responsible for the variation of the liquid contact angle, thus forming liquid micro-lenses. The temperature variation can generate a pattern of electric charges onto the surface of the crystal when ferroelectric domain pattern is micro-engineered. Different types of lenses: spherical, cylindrical and toroidal have been formed. Any temperature change allows the liquid layer to become a tunable micro-lens array, showing a strong focusing effect. A digital holography technique is used to characterize the transmitted wavefront during focusing and focal length variation in the millimetre range is observed. Formation process is illustrated while interferometric characterization and imaging properties are analyzed and discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tuneable liquid microlenses onto a functionalized polar dielectric substrates: formation and characterization

et al. 2010

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“…The new applications of tunable lenses requiring fast dynamic measurements of optical power impose new requirements for measurement instrumentation, far beyond the existing techniques. The static power of a lens can be measured by changing optical interdistances, between the lens and an object [25,26,28], an imaging screen or a camera [29,30]; or, as most ophthalmic lens meters do, by measuring the change in the interdistances of a collimator [31]. Aberrometers as Laser Ray Tracing [32] or Hartmann-Shack [33] are another option that provide not only optical power measurements, but also detailed information about the optical quality of the lens.…”

Section: Introductionmentioning

confidence: 99%

Tunable lenses: dynamic characterization and fine-tuned control for high-speed applications

Dorronsoro¹,

Barcala²,

Gambra³

et al. 2019

Opt. Express

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Tunable lenses are becoming ubiquitous, in applications including microscopy, optical coherence tomography, computer vision, quality control, and presbyopic corrections. Many applications require an accurate control of the optical power of the lens in response to a time-dependent input waveform. We present a fast focimeter (3.8 KHz) to characterize the dynamic response of tunable lenses, which was demonstrated on different lens models. We found that the temporal response is repetitive and linear, which allowed the development of a robust compensation strategy based on the optimization of the input wave, using a linear time-invariant model. To our knowledge, this work presents the first procedure for a direct characterization of the transient response of tunable lenses and for compensation of their temporal distortions, and broadens the potential of tunable lenses also in high-speed applications.

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“…Various approaches were investigated to fabricate either single microlenses or arrays made with different materials [1][2][3][4][5]. The possibility to change the focal length by thermal actuation was demonstrated with polydimethylsiloxane (PDMS) [6] and SU8 [7] polymeric single microlenses. Among the different classes of microlenses, lenses made with liquids have the main advantage that they can be easily tuned [1,2,4,[8][9][10].…”

mentioning

confidence: 99%

“…In the literature many authors have measured the focal length variations of liquid lenses by indirect calculations. Indeed, they calculated the height of the lens and then recovered the focal length or measured the focal spot formation [1,2,4,7,8]. We performed an interferometric DH analysis that allows a direct measurement of the focal length from the computed complex wavefront at the exit pupil of the lens.…”

mentioning

confidence: 99%

Hemicylindrical and toroidal liquid microlens formed by pyro-electro-wetting

et al. 2009

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We found that by opportune functionalization of a polar dielectric substrate, a self-arrangement of hemicylindrical or toroidal-shaped liquid droplets can be obtained. The process takes place when a thermal stimulus is provided to a poled substrate whose surface is covered by an oily substance layer. Liquid droplet self-arrangement is due to the pyroelectric effect, and interferometric characterization of the droplets is also reported. We investigated this open microfluidic system for exploring the possibility to obtain liquid cylindrical microlens with variable focal length. Liquid microtoroidal structures arrays are also realized. They could find application as resonant liquid microcavities for whispering gallery modes.

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Thermally tunable polymer microlenses

Cited by 23 publications

References 15 publications

Tuneable liquid microlenses onto a functionalized polar dielectric substrates: formation and characterization

Tuneable liquid microlenses onto a functionalized polar dielectric substrates: formation and characterization

Tunable lenses: dynamic characterization and fine-tuned control for high-speed applications

Hemicylindrical and toroidal liquid microlens formed by pyro-electro-wetting

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