Letter | Published:

Optical Images Formed by Conical Refraction

Naturevolume 149pages552553 (1942) | Download Citation



A PLATE of biaxial crystal cut approximately normal to the axis of single-ray velocity has the remarkable property of forming optical images of an illuminated object held in front of it. This effect was first observed with aragonite1 but is exhibited in a much more striking fashion by a plate of naphthalene prepared for the exhibition of conical refraction as described in a recent note2. The accompanying reproduction illustrates this phenomenon. 1 and 3 reproduce objects held in front of the crystal, while 2 and 4 are the corresponding images formed in the rear of the crystal and received directly on a photographic plate. The image recorded is in every case erect and of unit magnification. The distances of the object and of the image from the crystal faces may be independently varied from zero up to large values.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Raman, C. V., NATURE, 107, 747 (1921); Phil. Mag., 43, 510 (1922).

  2. 2

    Raman, C. V., et al., NATURE, 147, 268 (1941).

Download references

Author information


  1. Department of Physics, Indian Institute of Science, Bangalore

    • C. V. RAMAN
    •  & T. M. K. NEDUNGADI


  1. Search for C. V. RAMAN in:

  2. Search for T. M. K. NEDUNGADI in:

About this article

Publication history

Issue Date



Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.