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A MEMS based novel THz detector structure is designed and realized by micro fabrication. The detector is then characterized to extract its mechanical performance. Operating in 0.5–2 THz band, the detector has a pixel size of 200 μm × 200 μm. Bimaterial suspension legs consist of Parylene-C and titanium, the pair of which provides a high mismatch in coefficients of thermal expansion. The pixel is a suspended Parylene-C structure having a 200 nm-thick titanium metallization. Operation principle relies on conversion of absorbed THz radiation into heat energy on the pixel. This increases the temperature of the free-standing microstructure that is thermally isolated from the substrate. The increase in temperature induces mechanical deflection due to bimaterial springs. The detector is designed to deliver a detectivity (D*) of 2 × 109 cm Hz−1/2/W and a refresh rate of 20 Hz.

A micro-scanner made of stainless-steel is fabricated via laser cutting technology for 3D Lissajous confocal imaging. The multi-gimbaled structure of the device provides two orthogonal torsional modes and three different out-of-plane modes. Torsional modes can be used to achieve 2D scan and all of the out-of-plane modes can be used in changing the focus of the micro-scanner to achieve a 3D scanning pattern. One of the out-of-plane modes along with two orthogonal torsional modes can be employed for scanning a large depth-stack in sparse fashion while another out-of-plane mode can satisfy a much higher scan fill-rate with less field of view (FOV). Simulations of the micro-scanner are obtained using finite element method (FEM) software and compared with the characterization data gathered from Laser Doppler Vibrometer (LDV). Using various out-of-plane modes, the constructed fill patterns are simulated on MATLAB and fill rates compared.

Sub-10 nanometer lithography is opening a new area for beyond-CMOS devices. Regarding to single nano-digit manufacturing we have established a new maskless patterning scheme by using field-emission, current controlled Scanning Probe Lithography (cc-SPL) in order to create optical nanodevices in thin silicon-oninsulator (SOI) substrates. This work aims to manufacture split ring resonators into calixarene resist by using SPL, while plasma etching at cryogenic temperatures is applied for an efficient pattern transfer into the underlying Si layer. Such electromagnetic resonators take the form of a ring with a narrow gap, whose 2D array was the first left-handed material tailored to demonstrate the so-called left-hand behavior of the wave propagation. It is shown that the resonance frequency can be tuned with the feature size of the resonator, and the resonance frequency can be shifted further into near infrared or even visible light regions., Istanbul Development Agency (ISTKA)

A suspended array of square metallic patches on a thin dielectric layer is introduced as a terahertz absorber. The absorber is fabricated on a metalized substrate and the device exhibits metamaterial behavior at specific frequencies determined by the size of the patches. It is feasible to place patches with different sizes in an array formation for a broadband absorber. Design of the absorber is described using electromagnetic simulations. The absorber structure was fabricated on a silicon wafer and its characteristics were measured using a terahertz time domain spectroscope. The measured data match well the simulations indicating strong absorption peaks in a band of 0.5-2 THz.

A stainless-steel based micro-scanner with magnetic actuation is fabricated via laser-cutting technology targeted for confocal microscopy. Laser cutting offers low-cost and high speed fabrication of such scanners. The device is designed to establish a 2D Lissajous pattern. For a coil drive of 180 mA, fabricated scanner is able to deliver 4 degrees of optical scan angle for both slow scan and fast scan axes at 663 Hz and 2211 Hz, respectively. Fabricated mirror is integrated into a confocal microscopy setup and tested with the United States Air Force target accomplishing a 200 μm × 200 μm field of view and sub 10 μm resolution. With further improvement, our scanner will contribute to manufacturing of low-cost and compact scanning microscopy technologies.

This paper summarizes the design, fabrication, and characterization of a magnetically actuated stainless-steel based micro-scanner. The out-of-plane deflection of the proposed device is calculated by using a custom depth scan setup. The main advantage of laser cutting technology, which is utilized in manufacturing the proposed steel scanner, is its rapid fabrication capability at low cost, while still offering high frequency scan for imaging and/or ablation with high frame-rates. In the lateral plane, the scanner delivers 5 degrees of total optical scan angle for a current drive of 60 mA for both slow scan and fast scan axes at 998 Hz and 2795 Hz, respectively. Furthermore, the device provides an out-of-plane pumping mode at 1723 Hz that could be utilized for axial scanning to create focal shift at the target. Fabricated scanner is integrated into a confocal microscopy setup and tested with a resolution target and a Convallaria rhizome sample, accomplishing a 240 m 240 m field of view with 2.8 m resolution. The device offers 218 m depth of field (in tissue) and based on acquired resonance frequencies, we estimate rapid scanning of a three-dimensional block of tissue (240 m 240 m 218 m size) with approximately 3 block per second with 50% fill rate and total coverage of 87% for 1 s scan. Finally, a custom setup is proposed for 3D imaging and validity of the 3D beam steering of the micro-scanner is tested.

Glaucoma is an eye disease that may cause blindness by damaging the optic nerve due to elevation of the intraocular pressure. Patients with glaucoma require monitoring of intraocular pressure. This paper presents split-ring resonator-based strain sensors designed and characterized for glaucoma detection application. The geometry of the sensor is optimized such that it can be embedded in a conventional contact lens. Silver conductive paint is used to form the sensors realized on flexible substrates made of cellulose acetate and latex rubber. The devices are excited and interrogated using a pair of monopole antennas. Scattering parameters are measured between the ports of the antennas, and the characteristics of devices with different curvature profiles are obtained. Finite-element based models are developed to analyse the operation of the devices and to optimize the sensor structure. The sensitivity of the device, i.e. the change in resonant frequency for a unit change in radius of curvature, on acetate film is experimentally characterized as -4.73 MHz/mm and the sensitivity of the device on latex is 33.2 MHz/mm. The experimental results supported by finite-element based models indicate that the demonstrated device is suitable for glaucoma diagnosis and monitoring. (C) 2017 Elsevier B.V. All rights reserved.

This paper presents split-ring resonator-based strain sensors designed and characterized for glaucoma detection application. The geometry of the sensor is optimized such that it can be embedded in a contact lens. Silver conductive paint is to form the sensors realized on flexible substrates made of cellulose acetate and latex rubber. The devices are excited and interrogated using a pair of monopole antennas and the characteristics of devices with different curvature profiles are obtained. The sensitivity of the device, i.e. the change in resonant frequency for a unit change in radius of curvature, on acetate film is calculated as -4.73 MHz/mm and the sensitivity of the device on latex is 33.2 MHz/mm. The results indicate that the demonstrated device is suitable for glaucoma diagnosis.

A novel microelectromechanical systems (MEMS) actuation technique is developed for retinal scanning display and imaging applications allowing effective drive of a two-axes scanning mirror to wide angles at high frequency. Modeling of the device in mechanical and electrical domains, as well as the experimental characterization is described. Full optical scan angles of 65deg and 53deg are achieved for slow (60 Hz sawtooth) and fast (21.3 kHz sinusoid) scan directions, respectively. In combination with a mirror size of 1.5 mm, a resulting thetasopt D product of 79.5 degmiddotmm for fast axis is obtained. This two-dimensional (2-D) magnetic actuation technique delivers sufficient torque to allow non-resonant operation as low as dc in the slow-scan axis while at the same time allowing one-atmosphere operation even at fast-scan axis frequencies large enough to support SXGA (1280 times 1024) resolution scanned beam displays

A magnetically actuated microscanner is used in a laser scanning microscopy application. Stress distribution along the circular-profiled flexure is compared with a rectangular counterpart in finite-element environment. Magnetic actuation mechanism of the scanning unit is explained in detail. Moreover, reliability of the scanner is tested for 3×106 cycle. The scanning device is designed to meet a confocal microscopy application providing 100 μm×100 μm field of view and

We present a polymer-based mechanical sensor with an integrated strain sensor element. Conventionally, silicon has been used as a piezoresistive material due to its high gauge factor and thereby high sensitivity to strain changes in the sensor. By using the fact that the polymer SU-8 [1] is much softer than silicon and that a gold resistor is easily incorporated in SU-8, we have proven that a SU-8-based cantilever sensor is almost as sensitive to stress changes as the silicon piezoresistive cantilever. First, the surface stress sensing principle is discussed, from which it can be shown that the SU-8-based sensor is nearly as sensitive as the silicon based mechanical sensor. We hereafter demonstrate the chip fabrication technology of such a sensor, which includes multiple SU-8 and gold layer deposition. The SU-8-based mechanical sensor is finally characterized with respect to sensitivity, noise and device failure. The characterization shows that there is a good agreement between the expected and the obtained performance.

A two-axis microelectromechanical systems micromirror actuator is developed for retinal scanning display and imaging applications. The device operation makes use of magnetostatic torque produced by the combination of a flux generating custom-made high-frequency electrocoil and the NiFe layer deposited on the movable part. Modeling of the actuation in the magnetic domain, as well as the experimental characterization of the mechanical part is described. The device is capable of full optical scan angles of 88deg (at 100-mA root-mean-square coil current) and 1.8deg for slow and fast-scan directions, respectively. In combination with a mirror size of 1.5 mm, resulting thetasoptmiddotD products are 132degmiddotmm and 2.7degmiddotmm for slow and fast axis, respectively. Atmospheric operation of the device is enabled due to high mechanical quality factors of the order of 3000

A unique tunable microwave resonator with a pair of half-rings is introduced and validated by experimental data. The capacitive gap between the overlapping areas can be controlled accurately using a magnetic actuator for tunability. The design geometry is scalable to cover different bands of electromagnetic spectrum. Transmission characteristics of the resonators have been modeled using finite-element analysis and have been measured. The experimental results indicate the resonant frequency can be controlled with a resolution of a few MHz in a tuning range of 38%. The resonator exhibits sharp transmission dips within the tuning range with measured quality factors larger than 2500. (C) 2013 AIP Publishing LLC.

A two-dimensional (2D) polymer based scanning mirror with magnetic actuation is developed for imaging applications. Proposed device consists of a circular suspension holding a rectangular mirror and can generate a 2D scan pattern. Three dimensional (3D) printing technology which is used for implementation of the device, offers added flexibility in controlling the cross-sectional profile as well as the stress distribution compared to the traditional planar process technologies. The mirror device is developed to meet a portable, miniaturized confocal microscope application in mind, delivering 4.5 and 4.8 degrees of optical scan angles at 111 and 267 Hz, respectively. As a result of this mechanical performance, the resulting microscope incorporating the mirror is estimated to accomplish a field of view (FOV) of 350 µm × 350 µm.

An array of square metallic patches on a thin suspended dielectric layer is introduced as an effective terahertz absorber. The suspended structure is placed on a metalized substrate and the device exhibits metamaterial behavior at specific frequencies determined by the size of the patches. It is feasible to place patches with different sizes in an array formation for a broadband absorber. In array configuration, individual elements induce distinct resonances yielding narrow band absorption regions. Design of the absorber is described using electromagnetic simulations. The absorber structure was fabricated on a silicon wafer using standard microfabrication techniques. The characteristics of the absorber were measured using a terahertz time domain spectroscope. The measured data match well the simulations indicating strong absorption peaks in a band of 0.5-2 THz. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

In this work, a novel method for realization of a low-cost two-dimensional (2D) display is proposed. This method integrates a one-dimensional (1D) array of solid-state LEDs with 1D polymer scanner. LEDs are electronically modulated with a position sensing circuitry while Fire-Resistant 4 (FR4) scanner is actuated in perpendicular to modulation axis to produce a 2D display consisting of virtual pixels. The choice of polymer as the scanners' structural layer, utilization of just one row of LEDs and the simplicity of the process reduce the cost of fabrication drastically. Additionally, reduced number of light sources significantly increases the reliability of the display.

A novel, self-terminating electrochemical etch process is proposed for the fabrication of scanning steel micro-mirrors. The process uses single mask photolithography, and the etching step is terminated automatically, which at the same time enables the depth profile shaping of the fabricated structure. The proposed process is characterized and then used to fabricate two versions of one-dimensional (1D) steel micro-scanners: one with selective thinning of the predefined parts and one without thinning. The fabricated devices are characterized and compared with respect to their resonance frequencies and mechanical quality factors. The thickness of the starting substrate is selectively thinned down by approximately 150 μ mi n order to decrease the mass of the mirror and eventually to increase the resonance frequency of the fundamental mode. The resonance frequency of the structure is increased from 4210 Hz to 6060 Hz resulting in a normalized frequency shift of 15%. (Some figures in this article are in colour only in the electronic version)

A two axis Microelectromechanical System (MEMS) micromirror actuator is developed for display and imaging applications. The device operates on the principle of generated magnetostatic torque by a flux generating high-frequency electro coil and a magnetic layer deposited on the movable part. The device can supply full optical scan angles of 88 degrees (at 100 mA drive current) and 1.8 degrees for slow and fast scan directions, respectively. Using a mirror size of 1.5 mm, theta(opt)center dot D products of 132 deg-mm and 2.7 deg-mm for slow and fast axis are achieved, respectively. The scanner can be operated in air due to high mechanical quality factors of the order of 3000.

This paper describes the design, fabrication, and characterization of the first MEMS scanning mirror with performance matching the polygon mirrors currently used for high-speed consumer laser printing. It has reflector dimensions of 8mm × 0.75mm, and achieves 80° total optical scan angle at an oscillation frequency of 5kHz. This performance enables the placement of approximately 14,000 individually resolvable dots per line at a rate of 10,000 lines per second, a record-setting speed and resolution combination for a MEMS scanner. The scanning mirror is formed in a simple microfabrication process by gold reflector deposition and patterning, and through-wafer deep reactive-ion etching. The scanner is actuated by off-the-shelf piezo-ceramic stacks mounted to the silicon structure in a steel package. Device characteristics predicted by a mathematical model are compared to measurements., NA

Two-axis gimbaled scanner used in an SVGA display product with 58deg optical scan angle, 1.5 mm mirror size, and 21 KHz resonant frequency is reported. Scanner is actuated electromagnetically using a single coil on the outer frame and by mechanical coupling of outer frame motion into the inner mirror frame

This paper presents the fabrication and the test results of two-axis micromachined micro-mirror steel scanners developed for display and imaging applications. The novel fabrication method uses the conventional lithography and electrochemical metal etching techniques. A single photomask is used to define the whole structure, resulting in a simple and inexpensive fabrication process. Two different devices are designed, fabricated and characterized to test the proposed methods. Both of them employ the magnetostatic actuation to generate excitation force/torque. First device (Type-A) is a gimballed cantilever one, and it is capable of an optical scanning angle of 11.7° and 23.2° in slow- and fast-scan directions, consuming a power of 42 mW and 30.6 mW, respectively. This structure has a quality factor of 287 in the slow-scan direction and a quality factor of 195 in the fast-scan one. The second device (Type-B) is a gimballed torsional one, and it has an optical scanning angle of 76° and 5.9° in slow- and fast-scan directions, consuming 37 mW and 39 mW, respectively. This structure has a quality factor of 132 in the slow-scan and 530 in the fast-scan directions, respectively. The maximum total optical scanning angles obtained for the slow- and fast-scan axes are 105° (gimballed torsional device, Type-B) and 42° (gimballed cantilever device, Type-A).