Optics - Class & Quizes Flashcards
What is Polarization?
Polarization in optics refers to the orientation of the oscillations of electromagnetic waves, such as light, relative to the direction of the wave’s propagation.
Unlike waves that can oscillate in any direction perpendicular to their direction of travel (such as water waves), electromagnetic waves can oscillate in various directions at once.
When the oscillations are confined to a single plane, the light is said to be polarized.
What is Malus’s Law?
I = Iv0 cos^2(θ)
This law says that I is equal to I zero, times cos squared of Theta.
I is the intensity of the polarized light after passing through the polarizer.
Iv0 is the initial intensity of the polarized light before it hits the polarizer.
(It’s supposed to be I subscript 0 btw.)
θ is the angle between the light’s initial polarization direction and the axis of the polarizer.
WHat is phase shift?
In optics, phase shift refers to the change in phase angle of a wave of light or other electromagnetic radiation.
This shift occurs when a wave passes through a medium or reflects off a surface, leading to a change in the wave’s phase relative to its initial phase.
(The concept of phase shift is crucial in understanding various optical phenomena, such as interference, diffraction, and polarization.)
When does Bright Fringe happen in optics?
A “bright fringe” in optics typically occurs in the context of interference patterns, especially in experiments like Young’s double-slit experiment or in other setups where coherent light sources are used. Interference is the phenomenon where waves superimpose to form a resultant wave of greater or lesser amplitude. For light, this can manifest visually as patterns of bright (constructive interference) and dark (destructive interference) fringes.
WHat does Phase Shift mean?
–>WHat if, for example, our phase shift is a value of Pi?
A phase shift in the context of waves, including light, sound, or even quantum waves, refers to a change in the phase of one wave relative to another reference wave. Essentially, it’s a shift in the wave’s cycle position.
A phase shift of π radians (or 180 degrees) means that the wave has shifted by half of its wavelength.
WHat is a dark fringe?
A dark fringe is a region of minimal or zero intensity that results from destructive interference between two or more waves.
Dark fringes are formed when waves interfere destructively. This happens when the crest of one wave aligns with the trough of another wave, causing the waves to cancel each other out.
This is the opposite of bright fringe, which is where light interferes Constructively, doubling the wave amplitude.
What does fringe order mean?
What are fringes?
Fringe order, often denoted as m or n, quantifies the number of wavelengths of phase difference between two light waves at a given point in an interference pattern. It’s a measure of the relative displacement between the crests (or troughs) of the two interfering waves, essentially counting how many complete cycles of phase difference exist between them.
Recap the concept of Newton’s Rings.
Newton’s rings are a series of concentric circular bright and dark fringes resulting from the interference pattern of light waves reflected between a spherical lens surface and an adjacent flat glass surface.
Recap the concept of Michelson Interferometer.
Principle: The Michelson interferometer splits a beam of light into two paths using a beam splitter. One beam is reflected off a mirror moving perpendicular to the beam, and the other is reflected off a stationary mirror. The two beams are then recombined. The resulting interference pattern can be used to measure very small distances, such as changes in length due to thermal expansion or even gravitational waves, with high precision.
Are bright and dark fringes visible to the eye?
Yes, you can see both bright and dark fringes with your eyes under the right conditions. For example, in the double-slit experiment with visible light, if you shine a coherent light source (like a laser) through two closely spaced slits onto a screen, you can directly observe a pattern of alternating bright and dark bands with the naked eye.
At what point along a Michelson interferometer do the light rays combine?
–> What’s the gist of the steps that occur?
The light rays combine at the beam splitter after reflecting off the mirrors in the two arms of the interferometer.
Steps:
- Initial Splitting: Light from a coherent source hits a beam splitter (which is often a half-silvered mirror) positioned at a 45-degree angle. This splits the incoming beam into two paths: one beam reflects off the beam splitter towards one mirror (referred to as the reference arm), and the other beam passes through the beam splitter towards another mirror (referred to as the sample or measurement arm).
- Reflection from Mirrors: Each beam reflects off its respective mirror. In your question, one arm (the sample or measurement arm) contains an evacuated cylinder that gets filled with gas, while the other arm (the reference arm) is unchanged.
- Recombination at the Beam Splitter: After reflecting from the mirrors, the two beams return to the beam splitter. Here, part of the beam from the measurement arm passes through the splitter while part of it reflects; the same happens with the beam from the reference arm. Because of this, both beams are partially combined into a single beam that then heads towards a detection screen or an observer.
- Interference Pattern: The combined beams interfere with each other, producing an interference pattern (bright and dark fringes) on a screen placed to receive them. The pattern arises from differences in the path lengths traveled by the two beams, which are altered by changing conditions in the interferometer’s arms (such as introducing a gas into one arm in your question).
The change in the number of fringes observed when the gas is introduced is due to the change in the optical path length in the arm with the gas, compared to the vacuum or air path in the other arm. This difference in path length, caused by the difference in the refractive index of the gas compared to vacuum (or air), leads to a shift in the interference pattern.
If we have a magnification of -6 then:
- is the image enlarged or reduced in size?
- Is the image upright or inverted?
- The image is enlarged, and we know this because when ABSOLUTE VALUE of magnitude is greater than 1, then it’s enlarged. (and if its a decimal less than 1 then its reduced).
- Is the image upright or inverted?
The image is inverted, and we can tell this because an image is inverted when the magnification is negative.
