Understanding Optical Path Difference in Optics | OPD Explained

Click For Summary

SUMMARY

The discussion focuses on the calculation of Optical Path Difference (OPD) in optics, specifically the formula OPD = n2(AB + BC) - n1(AD). Participants clarify the significance of the refractive indices 'n1' and 'n2' and the path lengths involved. The negative sign in the formula indicates a subtraction of optical path lengths from different media. The geometric relationship between points C and D, which lie on the same wavefront, is emphasized to aid understanding of the OPD calculation.

PREREQUISITES

  • Understanding of refractive indices in optics
  • Familiarity with wavefront concepts
  • Basic knowledge of geometric optics
  • Ability to interpret optical path length calculations

NEXT STEPS

  • Study the principles of wavefronts in optics
  • Learn about the significance of refractive indices in optical calculations
  • Explore examples of Optical Path Difference in different media
  • Investigate the impact of geometric configurations on OPD calculations

USEFUL FOR

Students and professionals in optics, physicists, and engineers involved in optical design and analysis will benefit from this discussion.

moatasim23
Messages
77
Reaction score
0
SOme one help me with the OPD.
How is here the OPD=n2(AB + BC) -n1(AD)?
I am not confused with the introduction of 'n'..Rather the path length is confusing me..Why is there a negative sign?
 

Attachments

  • Path Difference.png
    Path Difference.png
    5.8 KB · Views: 1,399
Science news on Phys.org
They are computing a path difference ...
 
Just to elaborate a little on Simon's response.

Notice that the line connecting C and D is perpendicular to the rays. This indicates the C and D lie on the same wavefront.

Ergo, the OPD is calculated as the difference in optical path lengths from A-C and from A-D.

Claude.
 

Similar threads

Undergrad Difference between optical and geometrical length in optical path
  • · Replies 5 ·
Replies
5
Views
29K
Undergrad Prism Spectrometer Objective: Optics Question
  • · Replies 9 ·
Replies
9
Views
4K
How Does a Thin Film Alter the Optical Path Length?
  • · Replies 15 ·
Replies
15
Views
7K
Optical path difference between two reflected rays
  • · Replies 4 ·
Replies
4
Views
1K
Graduate The coherence length is much longer than the manufacturer claims
  • · Replies 10 ·
Replies
10
Views
4K
High School Multimode optical fiber, physics beginner help :D
  • · Replies 37 ·
2
Replies
37
Views
5K
Undergrad How Can I Build an Effective DIY Helmet-Mounted HUD?
  • · Replies 19 ·
Replies
19
Views
6K
Graduate Optical path length change due to absorption
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Condenser lens retrofit for a lighting application
  • · Replies 24 ·
Replies
24
Views
4K
Undergrad How Does Light Remain After Polarization Despite Changes in Its Electric Field?
  • · Replies 10 ·
Replies
10
Views
3K