PHYS 335- OPTICS

In alignment, iris 1 was closed and the light was carefully set to project through. Once this was complete, iris 2 was shifted into place while iris one was open and iris 2 was closed.

part two - Measuring beam width

With the same setup, a razor blade was placed between iris 1 and iris 2. The light sensor was also placed in front of iris 2, capturing the light. The beamwidth was measured by slowly "cutting" the light with the razor blade. With the help of CAPSTONE, we were able to determine the beam width.

Part 3 - INSTALLATION of telescope

Two convex lenses were used to manipulate the light. By doing so, we were able to create a telescope, where the light beam was magnified. Any object placed in front of the light beam was also shown larger.

part 4 - optical system

A spatial filter was created. Two lenses were used to shrink the beam width to travel through the iris and then expand to its original width. The lenses have identical focal distances.

part 4 cont. - optical system

We created a beam expander using diverging lenses. The light beam travels through the two lenses, both with different focal distances.

Task 3 Handout

Ray Diagrams Word doc

Geometrics Lab

Geometric Optics Lab

Task 4 - Simple Optical Devices

Total Internal Reflection

Total internal reflection of a laser through a prism occurs when a laser beam enters the prism at an angle greater than the critical angle for the interface between the laser medium and the prism material. This critical angle is determined by the refractive indices of the two materials involved. When the angle of incidence exceeds this critical angle, the laser light is completely reflected within the prism's boundaries, rather than being refracted or transmitted through it.

Beam Expander for Laser

A beam expander for a laser source is an optical device that enlarges or "expands" the diameter of a laser beam. It typically consists of lenses, where one lens converges or focuses the incoming laser beam, and another lens diverges or spreads the focused beam. This results in a larger laser beam diameter at the output, while maintaining the beam's collimation (parallel nature).

Basic Telescope

A basic telescope consists of two main optical components: an objective lens or mirror and an eyepiece. The objective lens or mirror gathers and focuses light from distant objects. The eyepiece then magnifies the focused image, making it easier to observe. Telescopes work by collecting more light than the human eye can, enabling us to see distant objects with greater clarity and detail.

Task 5 - Microscope build

In this basic microscope setup, a convex lens is employed for magnification. The lens is securely affixed to a translating stage, allowing precise movement for focus adjustments. Two apertures are incorporated, regulating the amount of light reaching the lens and enhancing image clarity. A laser light source is utilized for alignment, ensuring optimal positioning of the lens. This assembly provides a fundamental yet effective microscope for educational purposes, offering insights into microscopy principles.

Task 6 - Interference and Diffraction

Worksheet

Task 6 WS.docx

VIRTUAL Lab

Wave Interference Virtual Lab.docx

In our interferometer setup, we employed a laser as a coherent light source, directing it towards a beam splitter that divided the beam into two paths. An aperture was utilized to direct the beam more effectively. Mirrors were strategically placed along each path, and one mirror was adjustable to control path length. The beams were then recombined, allowing for interference, and the resulting pattern was captured. This interference pattern, visible on a screen, reveals information about the path length difference.

As seen above, a green laser was used for this setup. We were able to experimentally calculate the wavelength of the laser. The distance of mirror 1 was moved by a certain number of micrometers. We chose to make the first measurement of just one micrometer, then each one after at two micrometers. As the lens was rotated, the number of fringes that passed by the image, N, was calculated.

The wavelength calculated through the data represented less than a 10% error in comparison to the theoretical value of the green laser.

Task 7 - Poission's Spot

Named after physicist Siméon Denis Poisson, this phenomenon reveals the dual nature of light as both particles and waves. Utilizing a coherent light source like a laser and a small pin as an obstacle, we observed the occurrence of a bright spot in the shadow, defying classical predictions. The experimental setup involved adjusting the distance between the obstacle and a screen to optimize conditions for observing Poisson's Spot.

Task 10 - Final Build (Phase Contrast Microscope)

Task 10 - what is it?

A phase-contrast microscope is designed to enhance the contrast of transparent, unstained specimens that are difficult to observe under a standard bright-field microscope. This technique is handy for studying live cells, microorganisms, and other transparent specimens without the need for staining or fixing.

The key components of a phase-contrast microscope include a bright, white light source, a condenser with a phase annulus, phase plates in both the condenser and the objective lens, specialized phase-contrast objectives, a phase ring in the objective lens, a specimen stage for holding samples, lens to project the image back larger onto a screen. The combination of these components is crucial in creating phase differences for the final image.

The working principle of a phase-contrast microscope centers around exploiting the phase differences in light waves passing through different parts of a specimen. In transparent specimens, traditional bright-field microscopy lacks contrast. Phase contrast introduces phase shifts in the transmitted light through the use of phase rings and annular phase plates. These phase differences translate into variations in brightness and darkness, revealing details of the specimens.