Michael Ian Lapsley

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Michael Lapsley

http://michaellapsley.blogspot.com/
https://sites.google.com/site/michaellapsley/
https://sites.google.com/site/michaelianlapsley/
https://sites.google.com/site/lapsleyspace/

I graduated with a Bachelors of Science in Biomedical Engineering from Rose-Hulman Institute of Technology. I am currently in my fourth year as an Engineering Science PhD Candidate supervised by Prof. Tony Jun Huang. I am interested in all facets of Micro/Nanotechnology and am currently conducting research in the emerging field of Optofluidics.

Lapsley, M. I., et al., Lab Chip, 2011, DOI: 10.1039/C0LC00707B

We have developed a planar, optofluidic Mach–Zehnder interferometer for the label-free detection of liquid samples. In contrast to most on-chip interferometers which require complex fabrication, our design was realized via a simple, single-layer soft lithography fabrication process. In addition, a singlewavelength laser source and a silicon photodetector were the only optical equipment used for data collection. The device was calibrated using published data for the refractive index of calcium chloride (CaCl2) in solution, and the biosensing capabilities of the device were tested by detecting bovine serum albumin (BSA). Our design enables a refractometer with a low limit of detection (1.24 x 10^-4 refractive index units (RIU)), low variability (1 x 10^-4 RIU), and high sensitivity (927.88 oscillations per RIU). This performance is comparable to state-of-the-art optofluidic refractometers that involve complex fabrication processes and/or expensive, bulky optics. The advantages of our device (i.e. simple fabrication process, straightforward optical equipment, low cost, and high detection sensitivity) make it a promising candidate for future mass-producible, inexpensive, highly sensitive, label-free optical detection systems.

Figure: (a) Schematic of the device with arrows depicting the familiar light path of a Mach–Zehnder interferometer. (b) An experimental image of the device, post-insertion of optical fibers.

Lapsley, M. I., et al., Appl. Phys. Lett., Vol. 95, pp. 083507 (2009).

We introduce an optofluidic based variable optical attenuator with high stability, high reliability, simple and inexpensive fabrication, and an attenuation performance comparable to commercial devices. A standard soft lithography process produces a single-layered polydimethylsiloxane (PDMS) microfluidic device integrated with optical fibers. By altering the refractive index of the fluid within the microchannel, we can control the reflectivity of the fluid/PDMS interface and thus achieve variable attenuation. Theoretical calculations are conducted based on Snell’s law of refraction and the Fresnel equations of reflection, and the calculated attenuation response matches well with experimental data.

Figure: A schematic of the optical attenuator device. Altering the flow rates Q1 and Q2 changes the reflected power (R) of the incident beam (I).

Mao, X., et al., Lab Chip, Vol. 9, pp. 2050-2058 (2009).

We report a tunable optofluidic microlens configuration named the Liquid Gradient Refractive Index (L-GRIN) lens for focusing light within a microfluidic device. The focusing of light was achieved through the gradient refractive index (GRIN) within the liquid medium, rather than via curved refractive lens surfaces. The diffusion of solute (CaCl2) between side-by-side co-injected microfluidic laminar flows was utilized to establish a hyperbolic secant (HS) refractive index profile to focus light. Tailoring the refractive index profile by adjusting the flow conditions enables not only tuning of the focal distance (translation mode), but also shifting of the output light direction (swing mode), a second degree of freedom that to our knowledge has yet to be accomplished for in-plane tunable microlenses. Advantages of the L-GRIN lens also include a low fluid consumption rate, competitive focusing performance, and high compatibility with existing microfluidic devices. This work provides a new strategy for developing integrative tunable microlenses for a variety of lab-on-a-chip applications.

Figure: Principle and design of the L-GRIN lens. (A) A schematic diagram showing the comparison between the classic refractive lens (A1) and GRIN lens (A2). Change of the refractive index contrast in GRIN lens can result in change of focal distance (A2–A3), and shift of optical axis can result in change of output light direction (A4). (B) Schematic of the L-GRIN lens design (B1), microscopic image of the L-GRIN lens in operation (B2, left), and the expected refractive index distribution at two locations (I and II) inside the lens (B2, right). High optical contrast areas (dark streaks) were observed near the fluidic boundaries (B2, left), suggesting significant variation of refractive index due to the CaCl2 diffusion. (C) Schematic drawing showing two operation modes of the L-GRIN lens: the translation mode with variable focal length including no-focusing (C1), a large focal distance (C2), and a small focal distance (C3); and the swing mode with variable output light direction (C3–C5).

Mao, X., et al., Microfluidics Nanofluidics, Volume 8, Number 1, 139-144, DOI: 10.1007/s10404-009-0496-4 (2009)

In this study, we report a rapid microfluidic mixing device based on chaotic advection induced by microbubble–fluid interactions. The device includes inlets for to-be-mixed fluids and nitrogen gas. A side-by-side laminar flow segmented by monodisperse microbubbles is generated when the fluids and the nitrogen are co-injected through a flow focusing micro-orifice. The flow subsequently enters a series of hexagonal expansion chambers, in which the hydrodynamic interaction mong the microbubbles results in the stretch and fold of segmented fluid volumes and rapid mixing and homogenization. We characterize the performance of the microfluidic mixer and demonstrate rapid mixing within 20 ms. We further show that bubbles can be conveniently removed from the mixed fluids using a microfluidic comb structure on completion of the mixing.

Figure: Principle of the bubble-based chaotic mixer. (a) (From left to right) The formation of the bubble-segmented laminar flow between water and ink, the stretch and fold of the fluidic volume due to the bubble–fluid interaction in the mixing chamber, and fully mixed fluids. (b) The control experiment with a mixing chamber but no bubble. © The control experiment with bubbles but no mixing chamber. The water/ink flow rates were 0.2 ll/min for (a–c), and the gas pressures for (a) and © were 1 psi

Zhang, et al., Appl. Phys. Lett. 96, 013506 (2010); doi:10.1063/1.3290251

High temperature sensors are of major importance to aerospace and energy related industries. In this letter, a high temperature monolithic compression-mode piezoelectric accelerometer was fabricated using YCa4O(BO3)3 (YCOB) single crystals. The performance of the sensor was tested as function of temperature up to 1000 °C and over a frequency range of 100–600 Hz. The accelerometer prototype was found to possess sensitivity of 2.4 +- 0.4 pC/g, across the measured temperature and frequency range, indicating a low temperature coefficient. Furthermore, the sensor exhibited good stability over an extended dwell time at 900 °C, demonstrating that YCOB piezoelectric accelerometers are promising candidates for high temperature sensing applications.

Figure: Sensor charge as a function of acceleration at room temperature and elevated temperature of 900 °C (the small inset is the snapshot from Oscilloscope, showing the driving voltage and sensor voltage).

Ph. D. in Engineering Science - Pending Graduation in May 2013
Pennsylvania State University, State College, PA
Current GPA: 3.9/4.00

Bachelor of Science in Biomedical Engineering - Graduated cum laude in March 2007
Rose-Hulman Institute of Technology, Terre Haute, IN
Minor: Electrical Engineering
Concentration: Bioinstrumentation
GPA: 3.57/4.00

Research Engineer at TRS Technologies, State Collage, PA 5/7/08 - 8/1/11

• Developed technical reports and presentations for NASA research programs.
• Conducted electrical design of logic and high-voltage circuits for driving piezoelectric actuators and motors.
• Designed devices and testing systems for cryogenic traveling wave motors, cryogenic actuators, and high-temperature piezoelectric sensors.

Research Assistant - Penn State ~ 8/1/11 - Present

• Design and development of several devices in the filed of microfluidics and optofluidics including: a high speed bubble mixer, a Liquid-GRIN microlens with two degrees of freedom, a fluid controlled optical attenuator, and an optofluidic interferometer for refractive index detection.

Graduate Teaching Assistant - Penn State ~ 8/27/07 – 5/7/09

• Prepared and conducted lectures and recitations for undergraduate engineering courses.
• Tutored students, graded exams, managed grade books and completed other curse instruction tasks.

MEMS Laboratory Technician at Rose-Hulman ~ 3/5/07 – 8/10/07

• Maintained and operated equipment in MEMS lab (Mask Aligner, Plasma Asher, Sputter, etc.)
  
• Completed designs for MEMS based inertial activated thermal battery igniter.
  
• Supervised Student laboratory experiments for the undergraduate MEMS course.
  

ICTT – System Engineer, Terre Haute, Indiana ~ 6/1/06 – 8/20/06

• Implemented the System Engineering process into multiple software platforms
  
• Organized Stakeholder Needs and System Requirements linking them to System Features
  
• Designed Domain, Logical Architecture, and State Diagrams to model System Processes
  
• Compiled User Manuals for the system process and trained Project Engineers
  

Undergraduate Research and Projects ~ 9/1/03 – 3/4/07

• Worked with Suros Surgical designing and Manufacturing an innovative breast biopsy device.
  
• Designed Process Flow, then fabricated a Microfluidics device and studied electrophoresis
  
• Fabricated Micro Heat Actuators in a MEMS Clean Room (2 years of Clean Room Experience)
  
• Designed and developed an analog Thermometer with a large LED display to improve visibility
  
• Constructed devices for recording EMGs and EEGs.
  

Axogen – Nerve Regeneration, Gainesville, Florida ~ 6/1/04 – 7/1/04

• Conducted research on competition and emerging technologies in the field of nerve regeneration.
  
• Prepared a technical Reference Support Document, and stand-alone Stakeholder Presentation.
  

• President of Delta Sigma Phi Fraternity Zeta Lambda chapter ~ 2006 - 2007
• Vice-President of Delta Sigma Phi Fraternity Zeta Lambda chapter ~ 2005 - 2006

• Awarded the two year, NASA PSGC Graduate Research Fellowship ~ 2010 - 2012
• Awarded the Harry G. Miller Fellowship in Engineering ~ 2008
• Awarded the Paul H. Schweitzer Memorial Graduate Fellowship in Engineering ~ 2007
• 2011 ESM Today Symposium – 3rd Place in poster competition
• 2010 ESM Today Symposium - 2nd Place in poster competition
• 2009 ESM Today Symposium – 3rd Place in paper competition

1. Lapsley, Michael Ian, Chiang, I-Kao, Zheng, Yue Bing, Ding, Xiaoyun, Mao, Xiaole, and Huang, Tony Jun, A single-layer, planar, optofluidic Mach-Zehnder interferometer for label-free detection, Lab on a Chip, 2011, Accepted.
2. Lapsley, M. I., Lin, S.-C. S., Mao, X. & Huang, T. J., An in-plane, variable optical attenuator using a fluid-based tunable reflective interface, Applied Physics Letters, AIP, 2009, 95, 083507
3. Mao, X., Lin, S.-C. S., Lapsley, M. I., Shi, J.; Juluri, B. K. & Huang, T. J., Tunable Liquid Gradient Refractive Index (L-GRIN) lens with two degrees of freedom, Lab Chip, The Royal Society of Chemistry, 2009, 9, 2050-2058
4. Mao, X.; Juluri, B.; Lapsley, M.; Stratton, Z. & Huang, T., Milliseconds microfluidic chaotic bubble mixer, Microfluidics and Nanofluidics, 2009,
5. S. Zhang; Xiaoning Jiang, Michael Lapsley, Paul Moses and Thomas Shrout, Piezoelectric accelerometers for ultrahigh temperature application, Applied Physics Letters, 2010, 96, 013506

Department of Engineering Science and Mechanics
The Pennsylvania State University
Office: 328 Millennium Science Complex
University Park, PA 16802
Cell: 260-437-5264
E-mail: mil112@psu.edu

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