F. Levent Degertekin

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A miniature differential microphone is described having a low-noise floor. The sensitivity of a differential microphone suffers as the distance between the two pressure sensing locations decreases, resulting in an increase in the input sound pressure-referred noise floor. In the microphone described here, both the diaphragm thermal noise and the electronic(More)
We introduce a novel probe structure for the atomic force microscope. The probe has a sharp tip placed on a micromachined membrane with an integrated displacement sensor, a diffraction-based optical interferometer. We use this probe in a microscope to directly measure the transient interaction forces between the probe tip and the sample when operating in a(More)
The fabrication and characterization of a biomimetic MEMS directional microphone with integrated optical readout is presented. The use of diffraction-based optical interferometric detection with this novel microphone diaphragm avoids key limitations imposed by capacitive sensing, which is commonly used in miniature microphones. In this study, a(More)
We introduce a sensor for direct measurement of tip-sample interaction forces in probe microscopy. The sensor uses a micromachined membrane structure built on a transparent substrate with an integrated diffraction grating for optical interferometric detection, and a built-in electrostatic actuator. To demonstrate our concept for this sensor, we measured the(More)
A micromachined accelerometer device structure with diffraction-based optical detection and integrated electrostatic actuation is introduced. The sensor consists of a bulk silicon proof mass electrode that moves vertically with respect to a rigid diffraction grating backplate electrode to provide interferometric detection resolution of the proof-mass(More)
Ultrasound contrast agents (UCAs) have tremendous potential for in vivo molecular imaging because of their high sensitivity. However, the diagnostic potential of UCAs has been difficult to exploit because current UCAs are based on pre-formed microbubbles, which can only detect cell surface receptors. Here, we demonstrate that chemical reactions that(More)
A system of in situ ultrasonic sensors has been developed that can be used to monitor the photoresist prebake process. A high frequency phase measurement monitors the resist film properties while a lower frequency time of flight measurement monitors the corresponding wafer temperature. The high frequency measurement involves calculating the phase of an(More)
An actuation method for atomic force microscope ͑AFM͒ cantilevers in fluids is reported. The radiation pressure generated by a focused acoustic transducer at radio frequency ͑rf͒ ͑100–300 MHz͒ exerts a localized force of controlled amplitude at a desired location on the AFM cantilever. This force can be used to measure the spring constant and other dynamic(More)
In this paper, the flrst experimental results of pulse-echo imaging employing a 1-D capacitive microma-chined ultrasonic transducer array are presented. A 1-D array consisting of 16 elements is used in the experiment. A wire phantom consisting of seven steel wires immersed in vegetable oil is used as the imaging target. A B-scan image with a sector angle of(More)
The authors describe a method of actuation for atomic force microscope (AFM) probes to improve imaging speed and displacement range simultaneously. Unlike conventional piezoelectric tube actuation, the proposed method involves a lever and fulcrum "seesaw" like actuation mechanism that uses a small, fast piezoelectric transducer. The lever arm of the seesaw(More)