Optical-actuator frequency-coded pressure sensor.

Abstract: Overview Central topic of this thesis is the investigation of the quantum nature of light. This investigation is carried out in two separate experiments which are described in part I and part II respectively. In part I, classical and non-classical laser radiation is characterized at the quantum mechanical level with respect to its amplitude and phase uctuations, its photon number distribution and other observable quantities. This is done by employing recently developed methods of quantum state reconstruction. Such a complete characterization is of fundamental interest, since it can provide a much more detailed experimental description of light than previously known. Furthermore, since many experimental systems are analyzed by optical means, these methods may in future nd important applications in the characterization of such systems in full quantum mechanical detail, by determining the state of the light eld used as a probe before and after the interaction with the system. In part II, high precision position measurements via laser interferometry are investigated. Such measurements play an important role in the microscopic domain optome-chanical sensors, modern microscopy techniques as well as in the macroscopic domain development of large scale interferometers for the detection of gravitational waves. The goal of the second experiment is to explore the quantum mechanical limits in the precision with which the position of a macroscopic body can be determined. One common conceptual aspect of both experiments, besides the similar optical techniques employed, is that both attempt a high precision characterization of a harmonic oscillator system disturbed by stochastic noise. In part I, this oscillator is the light eld, subject to quantum noise, in part II, it is a mechanical harmonic oscillator excited by thermal noise. Further considerations about the connection and possible uniication of the two experiments can be found in the outlook to part II. The main results of the rst part of the thesis are i the complete mapping of the whole family of squeezed states of the light eld, that is light with reduced quantum noise. The values for noise suppression are among the highest achieved so far, ii the rst direct evidence of photon number oscillations in parametrically downconverted light, and iii the measurement of the rst-order time correlation function of the light eld of squeezed vacuum. The main result of the second part is the detection of the Brownian motion of a cryogenically cooled high-Q mechanical oscillator, using a high-nesse Fabry-Perot inter-ferometer. Displacements …

TL;DR: The feasibility of using an emitting diode (LED or laser diode) as both light transmitter and receiver in a single-fibre reflective sensor system has been demonstrated in this article.

TL;DR: In this paper, a miniature, resonant, fiber-optic scanner driven by silicon detector photocurrent requires only 23μW to sequentially address each channel of a ten-bit optical encoder mask.

TL;DR: An optically-driven, electro-mechanical actuator is described, which can sequentially connect a single multimode input fiber to each fiber of a 12-fiber array.

TL;DR: A novel concept for a digital optical position transducer that is electrically passive and requires only a dual-fiber optical link and has a 10-dB on–off contrast ratio and a 12-dB insertion loss.

TL;DR: In this article, the authors present devices to convert a wide range of physical and mechanical properties into a displacement which can subsequently generate an instrumentation signal, which can be used for transducer applications.

TL;DR: In this paper, an optically operated relay, a narrow-band audio-frequency resonator, and a self-commutating optically powered oscillator were demonstrated, and the authors demonstrated that optical fibers can bend and, by misaligned coupling, modulate guided light signals.

Abstract: This paper presents devices to convert a wide range of physical and mechanical properties into a displacement which can subsequently generate an instrumentation signal. The application of physical principles as the basis of a practical transducer is but one fascinating aspect of instrumentation. The reader should not expect to find the operating principles of all the devices explained in detail, but rather should use the pictorial presentation as a pot-pourri of physical ideas which can be dipped into at a first reading and used later as an aide-memoire to the range of available techniques. In many cases, for example the differential manometer, the principle of operation is quite elementary while in others, for example the Coriolis flowmeter, the principle of operation is hidden in the underlying physics. (Paper 6 describes the principle of operation of a Coriolis flowmeter in some detail.)