KGd(WO

4

)

2

laser crystal is a new laser substance material developed upon CaWO

4

crystal. Regardless operated in freedom

under control of Q value or LD pumping

it shows high efficiency. It has good mechanism and optics behave

and can be high-doped.It has potential in non-linearity and Raman scatter area. So the crystal supposes to be premising substance in the field of medical treatment

communication

electronics

remote sensing

industry and so on. Yb ion doping into this kind crystal can be used as femto-second laser material.Now it gets many attention and became a research hotspot. The absorption spectra and fluorescent spectra of Yb

3+

:KGW laser crystal were measured. From the absorption spectrum of Yb

3+

:KGW at room temperature

absorption peaks were found in the range from 900 to 1050nm

with three main peaks

982

954 and 936nm. The 982nm peak is the strongest absorption peak

which can match the emission wavelength of InGaAs LD. It means this kind crystal is suitable for LD pumping. Form the fluorescent spectrum

four fluorescent peaks

982

998

1017 and 1036nm were found. The 982nm is the strongest fluorescent peak but also strongest absorption peak

so the laser emission in this wavelength can't be realized but the wavelength of 1017 and 1 036nm can do it. Form the absorption and fluorescent spectrum

the value of stark energy spit was make out

with 10 682

10 471

10 188cm

-1

in up-level and 535

358

163

0cm

-1

in the down-level. Using Reciprocity method

the absorption cross-section

emission cross-section and fluorescent lifetime were calculated. The absorption cross-section is large

with the value of 1.43710

-19

cm

2

this means Yb

3+

:KGW is good for the absorption of pumping light.The value of emission cross-section is 2.44410

-18

cm

2

and it can used for laser emission.This crystal has longer fluorescent lifetime of 0.306ms

benefit for energy storage. Because KGW is double-axis crystal

has different character in each direction. The paper emphasize on the influence of this identity to its spectrum behave

take it suit for LD puming into account. The infection of palarization direction and incidence direction of pumping light to crystal fluorescent spectra were measured

it may be theory basis for design LD pumping solid laser. It was found that every state is different.So when LD pumping such laser crystal was designed

the incidence and polarization direction should be taken into account. The influence of the incidence direction seems stronger than that of the polarization direction. The fluorescent intension with different incidence direction is

I

c

>

I

b

>

I

a

and

I

Np

>

I

Ng

>

I

Nm

. When light incidence is in

c

axis and the polarization is parallel

b

axis

the flurescent intension is the strongest.