# Tag Info

1 vote

### Is it true to say no refraction takes place when a ray comes along normal drawn to interface?

From an incident angle $\alpha$, we can deduce refraction angle $\beta$ using Snell law as : $$\beta = \sin^{-1}\left(\sin \alpha \cdot \left[ \frac {n_\alpha}{n_\beta} \right] \right)$$ This ...
• 7,719

### Why do my glasses make the ground look tilted?

A cylindrical shape error in your eyes' lenses will tilt your horizon, but your brain gets used to that over time and your horizon seems level to you. When you put on the corrective lenses, this ...
• 75.3k

### Ideal lens surface to prevent spherical aberration

The lens you are looking for is called aplanatic lens. It is free of coma and spherical aberrations. As a single optical element, it is formed as a surface of revolution of a plane curve called ...
• 376
Accepted

### On the definition of ray (optics) and wavefront of light

What is the relation between these two meanings? For light these two definitions of light rays rays = lines of light radiating from a bright object rays = curves perpendicular to the wavefronts are ...
• 27.6k

### On the definition of ray (optics) and wavefront of light

Rays and wavefronts are used as visual aids to illustrate the passage of light. In geometrical optics light is assumed to travel in straight line if the medium does not change and in physical optics ...
• 79.7k

### On the definition of ray (optics) and wavefront of light

Geometric optics defines a light ray, roughly speaking and using modern terms, as the trajectory of a photon as a pure particle, which would be your second definition. Wave optics has to come up with ...
• 4,323

### Plane mirror with focusing/accommodation Question

20cm. Accommodation will be 20cm. If it would be 10cm, then the focus would be on the surface of the mirror. If you want to see specks of dust on the mirror, then your accommodation will be just the ...
• 1,018

### I seek a highly specular reflective (>99%) surface for UVC (~253.7 nm) photons. Is such a surface possible?

Your question seems to have two parts. Can you get the reflectivity > 99% The answer is yes. Dielectric mirror stacks can give you that. Does the reflectivity depend on angle of incidence The ...
• 1,721

### On the optical properties of quadrupolar magnets

The power of a lens is 1/f. Also sometimes called the strength of the lens. Stronger lenses bend the light more. The focus closer to the geometric optics lens. So I think that he is just saying a ...
• 1,721

### Image created by a parabolic mirror when the object is at the center of curvature

You are right! if you really construct a picture for any parabolic mirror and use more than just two rays , the meet at different points so there will mot be a sharp picture, in your image you could ...
• 3,682

### Image created by a parabolic mirror when the object is at the center of curvature

I think that it is an image in the Gaussian approximation: rays not very far away and not very inclined with respect to the axis of symmetry (approximate stigmatism). In this case, we can use the ...
• 3,231
1 vote
Accepted

### Is the Jones matrix always $2 \times 2$?

If the field is not paraxial, i.e. if the curvature of the wavefront cannot be neglected, then the field cannot be reduced to two components in the plane and a full 3D correlation matrix can be ...
• 39.5k

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