Clase 05: Mechanical Supports

Transcription

1 OptoMechanics Clase 05: Mechanical Supports Dr. Alejandro Farah Instituto de Astronomía, UNAM

2 content 2. Mechanical Supports Understanding the influence of mechanical support systems in the optical components Definición de fase, velocidad de fase, superposición de ondas y velocidad de grupo Principio de Huygens.

3 first of all a few words spatial stability, position and rotation, failure, human error

4 2.1.3 Definition of phase, phase velocity, superposition of waves and group velocity. The phase of an oscillation or wave is the fraction of a complete cycle corresponding to an offset in the displacement from a specified reference point at time t = 0. Phase is a frequency domain or Fourier transform domain concept, and as such, can be readily understood in terms of simple harmonic motion.

5 2.1.3 Definition of phase, phase velocity, superposition of waves and group velocity. Assumption: light is a harmonic wave (sinusoid) Phase speed of a wave: is the rate at which the phase of the wave propagates in space. The phase speed is given in terms of the wavelength λ (lambda) and period T as

6 2.1.3 Definition of phase, phase velocity, superposition of waves and group velocity. Equal phase (or cophased) Phase difference Out of phase

7 2.1.3 Definición de fase, velocidad de fase, superposición de ondas y velocidad de grupo. If two interacting waves meet at a point where they are in antiphase, then destructive interference will occur.

8 2.1.3 Definition of phase, phase velocity, superposition of waves and group velocity. It is common for waves of electromagnetic (light, RF), acoustic (sound) or other energy to become superposed in their transmission medium.

9 2.1.3 Definition of phase, phase velocity, superposition of waves and group velocity. When that happens, the phase difference determines whether they reinforce or weaken each other. Complete cancellation is possible for waves with equal amplitudes. The principle of superposition of waves states that the resultant displacement at a point is equal to the vector sum of the displacements of different waves at that point.

10 2.1.3 Definition of phase, phase velocity, superposition of waves and group velocity. Chromatic interference is seen in sea foam, which is made out of plankton. It is an example of the naturally occurring interference.

11 2.1.4 Huygen s principle. It recognizes that each point of an advancing wave front is in fact the center of a fresh disturbance and the source of a new train of waves; and that the advancing wave as a whole may be regarded as the sum of all the secondary waves arising from points in the medium already traversed.

12 HomeWork: Talking about teslescopes and astronomical instruments: i) How does interferometry work? ii) Is it possible for everyone to do optical interferometry? - What is a ray trace software? And mention at least 3 commercial softwares to do that.

13 P R O Y E C T O de O P T O M E C Á N I C A Objetivo: Realizar el diseño conceptual y preliminar de los soportes optomecánicos para el instrumento astronómico RATIR. Metas particulares: - Proponer métodos de soporte de componentes ópticos a nivel conceptual. - Evaluar el diseño de todos los componentes mecánicos de soporte propuestos para el proyecto. - Realizar el cálculo de esfuerzos, desplazamientos y rotaciones de los diferentes sistemas desarrollados. - Comparar el desempeño calculado con los requerimientos y especificaciones del instrumento.