The aim of the course is to give a deep knowledge on modern optical and optoelectronic measurements. Starting from basic measurements of truly optical parameters of LASER light (spectrum, power, coherence, beam profile) and going into the applications of optical instrumentation and measurements in scientific and technological fields. The class will study measurement methods and electro-optical systems, for electronic material and devices characterization (e.g. optical spectroscopy and laser interferometry), and optical methods and instrumentations for the optical communications, and electro-optical instrumentation for automotive and industrial applications such as optical telemeters, interferometers, laser vibrometers and velocitmeters.

We expect that the student will become able of understanding and solving problems related to optical instrumentation and measurements.

In particular, the ability of designing and using practical optical telemeters, interferometers, velocimeters and using optical laboratory instrumentation (optical power meter, optical spectrum analyzer, wavelength-meter) will be tested with written exercises and tests.

At the end of the course and after successfully passing the exam, the student should reach the following learning results, with reference to the Doublin Descriptors:

Knowledge and understanding (Dublin Descriptor 1)

• knows how to analyze block diagrams of optical measurements setups and to understand the choice of different laser sources on the system performance;
• knows how to design coherent optical detection systems evaluating signal and noise performance;
• understands how to use an optical telemeter, interferometer, velocimeter and optical measurement instrumentation (optical spectrum analyzer, optical power-meter, wavelength-meter).

Applying knowledge and understanding (Dublin Descriptor 2)

• is able to apply the acquired understanding to assess operation and performance of given optical measurement instrumentation;
• is able to apply the acquired knowledge and skills to design an optoelectronic sensor or an optical interferometer;
• is able to discuss pros and cons and performance trade-offs among different optical measurement instrumentation.

Making judgements (Dublin Descriptor 3)

• given a specific problem and project cases in the field of optical measurements, should be able to analyze the problem, highlight the peculiar requirements and characteristics, and to compare autonomously different choices in terms of HW and system performance.

Learning skills (Dublin Descriptor 5)

• will be able studying and understanding autonomously also different instrumentation from the one studied in the course;
• will be able understanding and calculating the limiting performance of different and new optical measurements and measurement systems;
• will be able deepening the knowledge in studied topics and reading and understanding scientific and technical publications dealing with laser instrumentation and optical measurements.

1. Review of incoherent/coherent optical sources and lasers, photodetectors, noise in optical oscillators (amplitude and frequency).
2. Laser telemetry: triangulators, Time-Of-Flight (pulsed/CW), LIDAR and DIAL.
3. Measurements on optical sources: emission spectrum, spatial profile and beam divergence of lasers and LEDs.
4. Optical power and energy measurements (optical power/energy meters). Polarization measurements. Optical Spectrum Analyzers (OSA). Monochromator and wavemeter for the measurement of optical wavelengths. Measurements for optical communications: Polarization Mode Dispersion (PMD); Optical Time Domain Reflectometry (OTDR); eye diagram and BER measurements on optical signal.
5. Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV), optical autovelox (tele-laser and laser-barrier).
6. Laser interferometry: Michelson, Mach-Zehnder, Sagnac, Twyman-Green, Double-Beam, Double-Frequency interferometers. Limits due to phase noise and quantum detection in laser interferometry. Electronic speckle‑pattern interferometry. Self-mixing interferometry. Interferometric techniques for industrial measurements: displacement, planarity, angle, and vibration measurements. Laser interferometry for Gravitational-Wave detection.
7. Measurements of temperature, intrusion, vibration, using optical fibers.

Essay optional topics

Stability and active stabilization of laser oscillators: natural and technical fluctuations of amplitude and frequency of the optical field and their suppression using optoelectronic control loops.

Ultra-high-resolutions optical measurements: hi-res and Doppler-free laser spectroscopy; atoms manipulation (laser cooling and trapping of atoms); optical frequency clocks.

No specific prerequisites are requested.

The exam consists of a written test on any of the topics of the course and of an optional oral interrogation.

No partial examinations are given during the semester.

The written test, approximately 1.5-to-2 hours long, is made of 3-to-4 exercises mostly based on theory applications and the corresponding numerical calculations. Some theoretical questions can be included in the written test. Logical order and clarity in answering the questions and solving the problems will be taken into account in the evaluation. Such classwork is appropriate for testing the expected learning results.

A large selection of previous classworks with solutions is available on the web page of the course.

The dates of the exams will be published well in advance in the class and on the web page of the course:

http://home.dei.polimi.it/svelto/didattica/index_didattica.html

Prof. Cesare Svelto phone: 02-2399.3610 e-mail cesare.svelto@polimi.it

Some 50% of the textbook can be used for a deeper insight of the topics described in the Course. The slides and other didactical material available on Course website are more than adequate for a full preparation of the exam.