Hengky Chandrahalim

Air Force Institute of Technology · Department of Electrical & Computer Engineering

An optoacoustic sensor includes a liquid crystal (LC) cell formed between top and bottom plates of transparent material. A transverse grating formed across the LC cell that forms an optical transmission bandgap. A CL is aligned to form a spring-like, tunable Bragg grating that is naturally responsive to external agitations providing a spectral tran...

A passive microscopic Fabry-Pérot Interferometer (FPI) pressure sensor includes an optical fiber and a three-dimensional microscopic optical enclosure. The three-dimensional microscopic optical enclosure includes tubular side walls having lateral pleated corrugations and attached to a cleaved tip of the optical fiber to receive a light signal. An o...

A passive microscopic Fabry-Pérot Interferometer (FPI) sensor includes a three-dimensional microscopic optical structure formed on a cleaved tip of the optical fighter using a two-photon polymerization process on a photosensitive polymer by a three-dimensional micromachining device. The three-dimensional microscopic optical structure having a hinge...

Herein, a two-photon nanostructuring process that is employed to monolithically integrate dynamic three-dimensional (3D) micromechanical features into Fabry–Pérot cavity (FPC) sensors on an optical fiber tip is demonstrated. These features represent a breakthrough in the integration and fabrication capabilities of micro optomechanical devices and s...

This work presents a multiphoton nanosculpting process that is employed to fabricate three-dimensional (3D) mechanically assisted optical resonant and nonresonant microsensors on fiber tips. The resonant microsensor consists of a complex 3D optical cavity design with submicron resolution and advanced micromechanical features including a hinged, mul...

Herein, a two-photon nanostructuring process that is employed to monolithically integrate dynamic three-dimensional (3D) micromechanical features into Fabry–Pérot cavity (FPC) sensors on an optical fiber tip is demonstrated. These features represent a breakthrough in the integration and fabrication capabilities of micro optomechanical devices and s...

A method is provided for fabricating a passive optical sensor on a tip of an optical fiber. The method includes perpendicularly cleaving a tip of an optical fiber and mounting the tip of the optical fiber in a specimen holder of a photosensitive polymer three-dimensional micromachining machine. The method includes forming a three-dimensional micros...

A passive microscopic Fabry -Perot Interferometer (FPI) sensor includes an optical fiber a three -dimensional microscopic optical structure formed on a cleaved tip of an optical fighter that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three- dimensional structure that is...

A method of making passive microscopic Fabry -Perot Interferometer (FPI) sensor includes forming a three -dimensional microscopic optical structure on a cleaved tip of an optical fiber that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three -dimensional structure that is s...

A team of researchers from both the Air Force Institute and Technology and Los Alamos National Laboratory are developing a paint that contains a material called quantum dots which can optically measure deformation of a surface. Quantum dots are the same materials used in new QLED television displays; however, they can also be used for a multitude o...

A passive microscopic Fabry-Perot Interferometer (FPI) sensor an optical fiber a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fiber that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three-dimensional structure that is subject to at...

Multimode optical switch is a key component of mode division multiplexing in modern high-speed optical signal processing. In this paper, we introduce for the first time a novel 2 × 2 multimode switch design and demonstrate in the proof-of-concept. The device composes of four Y-multijunctions and 2 × 2 multimode interference coupler using silicon-on...

A recent study by a team of government researchers considered the application of colloidal quantum dots applied as a paint to be used in next-generation optical deformation sensors, with the potential to simplify the non-destructive evaluation process.

This paper presents 3D Fabry–Pérot (FP) cavities fabricated directly onto cleaved ends of low-loss optical fibers by a two-photon polymerization (2PP) process. This fabrication technique is quick, simple, and inexpensive compared to planar microfabrication processes, which enables rapid prototyping and the ability to adapt to new requirements. Thes...

The adaptation of colloidal quantum dots loaded within a polymer for use in nondestructive testing can be used as an optical strain gauge due to the nanomaterial's strain sensing properties. In this paper, we utilized InP/ZnS colloidal quantum dots loaded within a polymer matrix applied onto the surface of a dog-bone foil pre-coated with an epoxy....

This paper presents 3-D optical cavities fabricated directly onto cleaved ends of optical fibers by local light-triggered polymerization. This fabrication technique is quick, simple, and inexpensive compared to standard microfabrication processes.

The on-chip quantum dot (QD) microcavity laser engineered on an annular groove made of fused silica was demonstrated based on the external quasi-cavity configuration. By incorporating an appropriate dose of polymer into QD film, the spectral purity of the lasing spectrum was significantly enhanced. In contrast to the dye microcavity laser embedded...

We developed chip-scale remote refractive index sensors based on Rhodamine 6G (R6G)-doped polymer micro-ring lasers. The chemical, temperature, and mechanical sturdiness of the fused-silica host guaranteed a flexible deployment of dye-doped polymers for refractive index sensing. The introduction of the dye as gain medium demonstrated the feasibilit...

The ink-jet technique was developed to print the wedge polymer microdisk lasers. The characterization of these lasers was implemented using a free-space optics measurement setup. It was found that disks of larger edge inclination angles have a larger free spectral range (FSR) and a lower resonance wavelength difference between the fundamental trans...

We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/°C based on a rhodamine 6G (R6G)-doped SU-8 whispering gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 μm height that provided detection sensitivity, and the chemically robust fused-silica microring resonator hos...

We investigated theoretically and experimentally the evanescent coupling between photonic waveguides of arbitrary shapes and refillable optical ring resonators on the same chip. The resonator hosts were designed to facilitate whispering gallery modes and etched by using a single-mask standard lithography process, whereas the waveguides were imprint...

We present refillable, ultralow-thresholds, and wavelength reconfigurable ring lasers on a fused-silica chip. These devices will enable various photonic and biochemical sensing applications that require sustainable, configurable, and low-threshold coherent light sources on a chip.

We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of t...

This publisher's note amends a recent publication [Opt. Express24(3), 2850-2857 (2016)] to include Acknowledgments.

We experimentally reporton optical binding of many glass particles in air that levitate in a single optical beam. A diversity of particle sizes and shapes interact at long range in a single Gaussian beam. Our system dynamics span from oscillatory to random and dimensionality ranges from 1 to 3D. The low loss for the center of mass motion of the bea...

This paper presents wavelength configurable on-chip solid-state ring lasers fabricated by a single-mask standard lithography. The single- and coupled-ring resonator hosts were fabricated on a fused-silica wafer and filled with 3,3'-Diethyloxacarbocyanine iodide (CY3), Rhodamine 6G (R6G), and 3,3'-Diethylthiadicarbocyanine iodide (CY5)-doped polymer...

We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing proces...

We fabricated a 3-D monolithically integrated optofluidic laser in a fused-silica chip using femtosecond laser pulses. Rhodamine 6G dissolved in quinoline was used as the gain medium and lasing was achieved at a pump threshold of 15 μJ/mm2.

We experimentally demonstrate clustering of spherical and non-spherical aerosols in a smooth optical-tweezers. Our empty trap has only a single local-minimum with additional minima being born by the aerosols that join the trap.

A digitally-tunable RF MEMS filter includes a substrate and a plurality of mechanically coupled resonators, wherein a first and a last resonator of the plurality of mechanically coupled resonators are configured to be electrostatically transduced. One or more of the plurality of mechanically coupled resonators are configured to be biased relative t...

A new generation of partially or even fully biodegradable implants is emerging. The idea of using temporary devices is to avoid a second surgery to remove the implant after its period of use, thereby improving considerably the patient's comfort and safety. This paper provides a state-of-the-art overview and an experimental section that describes th...

RLC resonators are used for wireless power/data transmission in short-range telemetry (inductive link). The biodegradable conductive polymer composites PLLA-PPy and PCL-PPy are used to fabricate RLC resonators, with the ultimate goal of making a fully biodegradable implant for in vivo operation. Modeling the RF conductivity of PLLA-PPy and PCL-PPy...

In this paper we present the characterization by galvanic coupling (direct contact) of radio-frequency (RF) driven RLC resonators made of different biodegradable materials, including biodegradable metals and new biodegradable conducting polymers. An equivalent electrical circuit is proposed based on the RLC resonator geometry and material propertie...

The ability to combine both actuation and sensing technologies into one unified MEMS fabrication process is enabling for a wide variety of applications including high frequency filters, transformers and mm-scale robotics. This research demonstrates piezoelectric MEMS (PiezoMEMS) devices based on lead zirconate titanate (PZT) thin films including sw...

This paper presents a direct electrical measurement technique of mechanically vibrating single-walled carbon nanotubes (SWCNTs) actuated up to microwave L-Band frequency regime. Acoustic resonances of suspended SWCNTs are detected by means of inherent average strain (<;ε>;) dependent piezoresistive property of the nanotubes. A novel combination of...

This paper presents the Butterworth-van Dyke model and quantitative comparison that explore the design space of lead zirconate titanate-only (PZT) and PZT on 3-, 5-, and 10-μm single-crystal silicon (SCS) high-overtone width-extensional mode (WEM) resonators with identical lateral dimensions for incorporation into radio frequency microelectromechan...

The objective of this research is to develop a completely polymeric and biodegradable RF driven RLC resonator circuit. New polymer composites are fabricated and characterized: they consist on conductive polymer nanoparticles (polypyrrole PPy) embedded in a biodegradable polymer matrix (both polylactide PLLA and polycaprolactone PCL are under invest...

This letter reports on the performances of a frequency-tunable lead-zirconate-titanate-transduced fully differential mechanically coupled high-overtone width-extensional filter. The demonstrated electric field tuning provides channel agility and bandwidth adjustability for the incorporation of analog spectral processors in modern radio receiver arc...

This paper provides the theoretical modeling, simulation, and quantitative comparison that explore the design space of PZT-only (Lead Zirconate Titanate) and PZT-on 3, 5 and 10 ¿m single-crystal silicon high-overtone width-extensional mode (WEM) resonators with identical lateral dimensions for incorporation into radio frequency microelectromechanic...

This paper reports the design and optical characterization of PZT transduced high-overtone width-extensional mode resonators with resonance frequency above 1 GHz. For the first time, a novel technique to measure resonance frequencies and vibrations of contour-mode resonators optically up to 1.2 GHz using only a 618 MHz carrier frequency is demonstr...

This paper shows the first successful combination of dielectrically-transduced 200 MHz resonators with the epi-silicon encapsulation process, and demonstrates a set of important capabilities needed for the construction of CMOS-compatible RF MEMS components. The result shows the resonant frequency of 207 MHz and a quality factor of 6,400. The high f...

This paper provides the first experimental demonstration of monolithically integrated piezoelectric MEMS RF switches with contour mode filters. Lead zirconate titanate (PZT) thin films are utilized to enable both low-voltage switch operation and filter tunability. This research leverages previous work using PZT actuators for low-voltage, wide-band...

This paper provides a quantitative comparison and explores the design space of lead zirconium titanate (PZT)–only and PZT-on-silicon length-extensional mode resonators for incorporation into radio frequency microelectromechanical system filters and oscillators. We experimentally measured the correlation of motional impedance (R_X) and qua...

This paper provides the theoretical modeling, simulation, and quantitative comparison that explore the design space of PZT-only (Lead Zirconate Titanate) and PZT-on 3, 5 and 10 ¿m single-crystal silicon high-overtone width-extensional mode (WEM) resonators with identical lateral dimensions for incorporation into radio frequency microelectromechani...

This paper reports on the design of a 2-pole differential MEMS filter using mechanically-coupled overtone width-extensional resonators. The resonators and filters are fabricated in the 10 mum thick device layer of a SOI wafer and transduced by a 0.5 mum PZT (lead zirconate titanate) thin film deposited on the top surface of the wafer. A 206.3 MHz o...

This paper reports on the design of a bandwidth-tunable RF MEMS filter using a series-coupled array of dielectrically-transduced square-extensional mode resonators. The proposed digital tuning scheme provides channel-agility and bandwidth granularity for analog spectral processors and RF spectrum analyzers. The resonators and filters are fabricated...

In this article, we report on the successful demonstration of lead zirconate titanate (PZT) thin film based MEMS devices for use in radio frequency (RF) systems. Both series and shunt switches operating at or below 10 V and 15 V, respectively, have been developed capable of operating over a wide temperature range. These switches have also been inte...

This paper provides a quantitative comparison and explores the design space of PZT-only (Lead Zirconium Titanate) and PZT-on- Silicon length-extensional mode resonators for incorporation into RF MEMS filters and oscillators. We experimentally measured the correlation of motional impedance (RX) and quality factor (Q) with the resonators' silicon lay...

This paper demonstrates an electrostatic transducer for lateral contour-mode resonators in which the transduction gaps are filled with a liquid dielectric (water) having much higher permittivity than air ( kappa_water = 80.1). Aqueous transduction is more efficient than air-gap transduction (lower motional impedance) and has a higher freq...