折射率改变材料

（1）用a repetition rate of 1 kHz. a wavelength of 800 nm. 40×, NA = 0.65 microscope objective在LiNbO3中能诱导负的折射率改变

FIGURE 1 Refractive index profiles of two typical waveguides measured

with a shearing interference microscope at a wavelength of 550 nm. (a) Δne

and (b) Δno of a waveguide in z-cut LiNbO3 written with 1 μJ, 420 fs pulses.

(c) Δne and (d) Δno of a waveguide in an x-cut crystal written with 0.2 μJ,

380 fs pulses. (e) Waveguide mode field at a wavelength of 633 nm corresponding

to the refractive index profile of (c)

Both structures show an increase solely in the extraordinary index n e. The ordinary index n o is decreased in both crystals. （上图中n e.均有上升，而n o均有下降）

At lower intensities, an increase of the extraordinary refractive index n e was observed that can be used to form high-quality optical waveguides. Higher intensities cause a decrease of no and ne accompanied by stress in the surrounding crystal as well as material damage.（在激光强度较高的时候n o和n e.均有下降）

Structural properties of femtosecond laser-induced modifications in LiNbO3

j. burghoff1,_h. hartung1s. nolte1a. t ¨unnermann1,2

(2)在UBK7（74SiO2 10B2O3 15Na2O/K2O1BaO)

FP10（10Sr(PO3)2 35AlF3 30CaF2 15SrF2 10MgF2)

FP20（20Sr(PO3)2 30AlF3 22CaF2 18SrF2 10MgF2）

中会产生负的折射率

Femtosecond-laser-writing in various glasses

D. Ehrt a,*, T. Kittel a, M. Will b, S. Nolte b, A . Tu¨nnermann b Journal of Non-Crystalline Solids 345&346 (2004) 332–337

激光光源为：约50fs pulses with a repetition rate of 1kHz at a wavelength of 800nm was used

文中说到折射率的改变不仅和写入波导的条件有关，还和玻璃的组份和结构有一定的关系。

(3)在Nd3t-doped BK7 glass中会有折射率的降低。

Laser writing of waveguides in photosensitive glasses

Heike Ebendorff-Heidepriem

Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK

激光光源为UV-laser 244 nm

（4）在商业铒镱共掺磷酸盐玻璃中，在在低重频1KHz的飞秒激光下，可以实现正和负的折射率改变

Origin of the refractive index modification of femtosecond laser processed doped phosphate glass

The origin of the local refractive index modification in femtosecond laser inscribed structures has been investigated with confocal microfluorescence imaging. We have identified the origin of both, positive and negative refractive index changes in a commercial Er-Yb codoped phosphate glass upon irradiation in the low repetition rate regime (1 kHz).

（5）Femtosecond time‐resolved refractive index changes in CdS（0.75）Se（0.25）and CdS

激光光源为：120 fs pulses at λ=620 nm，100‐μm‐thick single crystals of CdS0.75Se0.25 and CdS at 295 K

文章提到在I=3 GW/cm2会有一个瞬时的负的折射率改变，在更高的强度下改变的时间更长，当I=30 GW/cm2时会有10ps的改变，然后会有部分的恢复。

（6）铝硅酸盐玻璃的折射率变化为正，其他的玻璃表现出负的或者不均匀的折射率变化

Femtosecond laser-induced refractive index modification in multicomponent glasses

文中在多组分的玻璃中用激光诱导折射率改变，硼酸镧和钠磷酸盐玻璃，硼硅，铝硅酸盐，和重金属氧化物，通过使用高空间分辨率的折射率分析技术。对各种组分的玻璃进行了分析。