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Buzzin A, Giannini L, Bocchetta G, Notargiacomo A, Giovine E, Scorza A, Asquini R, de Cesare G, Belfiore NP. On the Dependency of the Electromechanical Response of Rotary MEMS/NEMS on Their Embedded Flexure Hinges' Geometry. Micromachines (Basel) 2023; 14:2229. [PMID: 38138399 PMCID: PMC10745469 DOI: 10.3390/mi14122229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/06/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
This paper investigates how the electromechanical response of MEMS/NEMS devices changes when the geometrical characteristics of their embedded flexural hinges are modified. The research is dedicated particularly to MEMS/NEMS devices which are actuated by means of rotary comb-drives. The electromechanical behavior of a chosen rotary device is assessed by studying the rotation of the end effector, the motion of the comb-drive mobile fingers, the actuator's maximum operating voltage, and the stress sustained by the flexure when the flexure's shape, length, and width change. The results are compared with the behavior of a standard revolute joint. Outcomes demonstrate that a linear flexible beam cannot perfectly replace the revolute joint as it induces a translation that strongly facilitates the pull-in phenomenon and significantly increases the risk of ruptures of the comb-drives. On the other hand, results show how curved beams provide a motion that better resembles the revolute motion, preserving the structural integrity of the device and avoiding the pull-in phenomenon. Finally, results also show that the end effector motion approaches most precisely the revolute motion when a fine tuning of the beam's length and width is performed.
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Affiliation(s)
- Alessio Buzzin
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy; (L.G.); (R.A.); (G.d.C.)
| | - Lorenzo Giannini
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy; (L.G.); (R.A.); (G.d.C.)
| | - Gabriele Bocchetta
- Department of Industrial, Electronic and Mechanical Engineering, Roma Tre University, Via Della Vasca Navale 79, 00146 Rome, Italy; (G.B.); (A.S.); (N.P.B.)
| | - Andrea Notargiacomo
- Institute of Photonics and Nanotechnologies, National Research Council IFN-CNR, Via Del Fosso Del Cavaliere 100, 00133 Rome, Italy; (A.N.); (E.G.)
| | - Ennio Giovine
- Institute of Photonics and Nanotechnologies, National Research Council IFN-CNR, Via Del Fosso Del Cavaliere 100, 00133 Rome, Italy; (A.N.); (E.G.)
| | - Andrea Scorza
- Department of Industrial, Electronic and Mechanical Engineering, Roma Tre University, Via Della Vasca Navale 79, 00146 Rome, Italy; (G.B.); (A.S.); (N.P.B.)
| | - Rita Asquini
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy; (L.G.); (R.A.); (G.d.C.)
| | - Giampiero de Cesare
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy; (L.G.); (R.A.); (G.d.C.)
| | - Nicola Pio Belfiore
- Department of Industrial, Electronic and Mechanical Engineering, Roma Tre University, Via Della Vasca Navale 79, 00146 Rome, Italy; (G.B.); (A.S.); (N.P.B.)
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Buzzin A, Asquini R, Caputo D, de Cesare G. Sensitive and Compact Evanescent-Waveguide Optical Detector for Sugar Sensing in Commercial Beverages. Sensors (Basel) 2023; 23:8184. [PMID: 37837014 PMCID: PMC10574832 DOI: 10.3390/s23198184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/13/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023]
Abstract
This work presents a compact and sensitive refractive index sensor able to evaluate the concentration of an analyte in a sample. Its working principle leverages on the changes in the optical absorption features introduced by the sample itself on the evanescent waves of a light beam. The device's high compactness is achieved by embedding the sample-light interaction site and the detector in a 1 cm2 glass substrate, thanks to microelectronics technologies. High sensitivity is obtained by employing a low-noise p-i-n hydrogenated amorphous silicon junction, whose manufacture process requires only four UV lithographic steps on a glass substrate, thus ensuring low production costs. The system's capabilities are investigated by sensing the sugar content in three commercial beverages. Sensitivities of 32, 53 and 80 pA/% and limits of detection of 47, 29 and 18 ppm are achieved. The above performance is comparable with state-of-the-art results available in the literature, where more complex optical setups, expensive instrumentation and bulky devices are used.
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Affiliation(s)
- Alessio Buzzin
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy; (R.A.); (D.C.); (G.d.C.)
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Abstract
In this paper we review the state of the art in the field of liquid-crystal tunable guided-wave photonic devices, a unique type of fill-once, molecular-level actuated, optofluidic systems. These have recently attracted significant research interest as potential candidates for low-cost, highly functional photonic elements. We cover a full range of structures, which span from micromachined liquid-crystal on silicon devices to periodic structures and liquid-crystal infiltrated photonic crystal fibers, with focus on key-applications for photonics. Various approaches on the control of the LC molecular orientation are assessed, including electro-, thermo- and all-optical switching. Special attention is paid to practical issues regarding liquid-crystal infiltration, molecular alignment and actuation, low-power operation, as well as their integrability in chip-scale or fiber-based devices.
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Affiliation(s)
- D C Zografopoulos
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi (CNR-IMM), Via del fosso del cavaliere, 100, 00133, Rome, Italy.
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Gilardi G, De Sio L, Beccherelli R, Asquini R, d'Alessandro A, Umeton C. Observation of tunable optical filtering in photosensitive composite structures containing liquid crystals. Opt Lett 2011; 36:4755-4757. [PMID: 22179873 DOI: 10.1364/ol.36.004755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the investigation and characterization of an optically tunable filtering effect, observed in a waveguide grating made of alternated strips of photocurable polymer and a mixture of azo-dye-doped liquid crystal. The grating is sandwiched between two borosilicate glasses, one of which includes an ion-exchanged channel waveguide, which confines the optical signal to be filtered. Exposure to a low power visible light beam modifies the azo-dye molecular configuration, thus allowing the filtered wavelength to be tuned over a 6.6 nm range. Simulations of the filtering response are well described with our experimental findings.
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Affiliation(s)
- Giovanni Gilardi
- Dipartimento di Ingegneria dell'Informazione, Elettronica e Telecomunicazioni, Sapienza Università di Roma, Rome, Italy.
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Gilardi G, Asquini R, d'Alessandro A, Assanto G. Widely tunable electro-optic distributed Bragg reflector in liquid crystal waveguide. Opt Express 2010; 18:11524-11529. [PMID: 20589013 DOI: 10.1364/oe.18.011524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We propose and numerically investigate a versatile and easy-to-realize configuration for a guided-wave voltage-tunable distributed feedback grating based on reorientation in nematic liquid crystal and coplanar comb electrodes. The device has a wide tuning range exceeding 100 nm and covers C and L bands for wavelength division multiplexing.
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Affiliation(s)
- Giovanni Gilardi
- Dipartimento di Ingegneria Elettronica, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy
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Abstract
We design a distributed feedback guided-wave device in liquid crystals, utilizing a simple geometry based on electro-optic molecular reorientation in uniaxial nematics. We numerically test the structure and demonstrate an effective Bragg reflector with voltage-tunable resonance.
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Affiliation(s)
- Domenico Donisi
- Department of Electronic Engineering, University of Rome Sapienza, Rome, Italy
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Caputo R, De Luca A, De Sio L, Pezzi L, Strangi G, Umeton C, Veltri A, Asquini R, d’Alessandro A, Donisi D, Beccherelli R, Sukhov AV, Tabiryan NV. POLICRYPS: a liquid crystal composed nano/microstructure with a wide range of optical and electro-optical applications. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1464-4258/11/2/024017] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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d'Alessandro A, Donisi D, De Sio L, Beccherelli R, Asquini R, Caputo R, Umeton C. Tunable integrated optical filter made of a glass ion-exchanged waveguide and an electro-optic composite holographic grating. Opt Express 2008; 16:9254-9260. [PMID: 18575489 DOI: 10.1364/oe.16.009254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report the fabrication and the optical characterization of a hybrid tunable integrated optical filter. It consists of a diffused ion-exchanged channel waveguide on a borosilicate glass substrate with a cover of the same glass to form a gap filled with a holographic grating. The grating morphology, called POLICRYPS (POlymer LIquid CRYstal Polymer Slices), is made of alternating stripes of polymer and liquid crystal acting as overlayer for the underneath waveguide. The filter structure includes aluminum coplanar electrodes to electrically control the grating properties, allowing the tunability of the filter. The electric driving power required to tune the filter obtained was in the range of submilliwatts due to the efficient liquid crystal electro-optic effect.
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Affiliation(s)
- Antonio d'Alessandro
- Dipartimento di Ingegneria Elettronica, Sapienza Università di Roma, Via Eudossiana 18, 00184 Rome, Italy.
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Abstract
We propose a versatile guided-wave geometry encompassing electro-optic control for signal routing. A zero-gap directional coupler in liquid crystal can switch between two output states in the guide plane, permitting signal rerouting with modulation voltages as small as 70 mV. In the absence of an applied bias, no guiding--hence no modal output--is provided by the structure.
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Affiliation(s)
- Rita Asquini
- Department of Electronic Engineering and Istituto Nazionale per la Fisica della Materia, University of Rome La Sapienza, Via Eudossiana 18, 00184 Rome, Italy.
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Abstract
We demonstrate a compact, low-power and broadband electro-optic switch in a simple waveguide geometry with undoped nematic liquid crystals. We experimentally achieve near infrared switching and signal routing with voltage modulations as low as 0.21V and a device length of 0.16mm.
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d'Alessandro A, Asquini R, Gizzi C, Caputo R, Umeton C, Veltri A, Sukhov AV. Electro-optic properties of switchable gratings made of polymer and nematic liquid-crystal slices. Opt Lett 2004; 29:1405-1407. [PMID: 15233450 DOI: 10.1364/ol.29.001405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report the diffraction properties at wavelengths of 632.8 and 1550 nm for volume transmission gratings made of a sequence of continuously aligned nematic liquid-crystal layers separated by isotropic polymer slices. The gratings are generated by holographically curing a solution of liquid crystal diluted in an isotropic prepolymer by means of a laser beam at a wavelength of 352 nm with a total intensity of approximately 10 mW/cm2. A diffraction efficiency of 98% was measured, and an electric field as low as 5 V/microm switches off the phase grating. Measured angular spectra are fitted by use of the modified coupled-mode theory including the effects of grating birefringence.
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Affiliation(s)
- A d'Alessandro
- Department of Electronic Engineering, University of Rome La Sapienza, National Institute for the Physics of Matter, Via Eudossiana 18, 00184 Rome, Italy.
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Henninot JF, Debailleul M, Asquini R, d Alessandro A, Warenghem M. Self-waveguiding in an isotropic channel induced in dye doped nematic liquid crystal and a bent self-waveguide. ACTA ACUST UNITED AC 2004. [DOI: 10.1088/1464-4258/6/4/005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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