DPSS laser with " NEAR TEM00 "

[Stefano Sica]

I introduce myself,
my name is Stefano Sica, live and work in south Italy as physics laboratory teacher.
The holography has been impassioning me for many years but I has never realized holograms.
Being an absolute beginner, I ask you if you have ever used DPSS laser with " NEAR TEM00 "
transverse mode as this http://www.dta.it/product.php?id_product=66, to make holograms.
I thank you in advance for the suggestions that you will give me, hoping soon to be able to make some hologram.

Stefano Sica

[dave battin]

dont buy it "near TM00", is no good for holography

i just listed this one this morning .................

http://cgi.ebay.com/Coherent-215M-laser ... 4cedf45af5

[DJ Mathson]

Hi Stefano Sica.

Welcome to the forum.

For the particular laser you link to, they also state that it has a linewidth of 0.1 nm. This is too large to get any usable coherence length.

The coherence length for a Gaussian beam with the wavelength of 635 nm and the linewidth of 0.1 nm is only 2 mm according to:
CL = 2ln(2) λ2/πΔλ = 2ln(2)(635*10-9)2/π(0.1*10-9) m = 2 mm

(where λ is the laser wavelength in meter, and Δλ is the spectral linewidth in meter.)


For display holography you usually want to have at least 15 cm of coherence length (longer is better). For a 635 nm laser this equals to a linewidth of approx 0.001 nm according to:
Δλ = 2ln(2) λ2/πCL = 2ln(2)(635*10-9)2/π(0.15) m = 1.2 * 10-12 m = 0.0012 nm

[Stefano Sica]

Thanks Dave and Dj Mathson, has saved me from a bad purchase

Stefano

[Tom B.]

For display holography you really want pure Single Longitudinal Mode (SLM) and recommendations from holographers who have tried the laser. And a no-hassle return policy if the laser is not suitable. Low-level side-modes that are not at all important for most laser customers are visible as ugly unwanted contour lines on display holograms.

[Cristiano_Perrucci]

Hi Stefano,
I sent you a PM.

Cristiano