Optical constants

Refractive index of LiGaS₂ (Lithium gallium sulfide, LGS)

Kato et al. 2017: n(α) 1.025–10.591 µm

Data: formula 4
Range: 1.025–10.59 µm
Optical axis: alpha
Licence: CC0-1.0

Biaxial crystal, axes: alpha

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 2.0727
Extinction coefficient k: 0

Permittivity ε₁: 4.29609
Permittivity ε₂: 0

Absorption coefficient α: 0 cm⁻¹
Penetration depth δ = λ/(2πk): — nm

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.00581037 µm⁻¹

Group index n_g: 2.09182
Group velocity dispersion: -5.25373 fs²/mm

Dispersion parameter D: 0.914274 ps/(nm·km)
Photon energy: 0.376852 eV

ε = (n + ik)², α = 4πk/λ, n_g = n − λ dn/dλ, GVD = λ³/(2πc²) d²n/dλ², D = −(λ/c) d²n/dλ². Group-velocity dispersion is given for formula data only.

Use it in Lightsmith

Load this data in Python, simulate in one more line

pip install lightsmith

import lightsmith as ls

# LiGaS2 (Lithium gallium sulfide, LGS): Kato et al. 2017: n(α) 1.025–10.591 µm
ligas2 = ls.fetch_refractiveindex("main", "LiGaS2", "Kato-α", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(ligas2.range_nm)  # (1025, 10591) nm
eps = ligas2.eps([3290])  # complex permittivity

Downloads the original record once (pinned to the imported snapshot) and caches it.

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_c456e2ea920b/lightsmith"
ligas2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(ligas2.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (ligas2/kato-2017).

# ... load ligas2 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=ligas2)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=1025, stop_nm=10590, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength

Same spec runs with DDA, FDTD, BEM or T-matrix: ls.compare(sim, ["mie", "dda"]).

Materials guide Open a sphere of it in Studio Quick start Ask the community

Lightsmith is open source (MIT): Mie, T-matrix, BEM, DDA, FDTD, RCWA, TMM, mode solvers and inverse design behind one spec, on CPU or GPU. GitHub.

Dispersion formula

RefractiveIndex.INFO (formula 4), λ in µm

n^{2} = 5.40285 + \frac{0.1105 λ^{0.0}}{λ^{2} - {0.03238}^{1.0}} + \frac{460.11 λ^{0.0}}{λ^{2} - {422.74}^{1.0}}

Valid from 1.025 to 10.591 µm.

Coefficients as stored

C_i	Value
C1	5.40285
C2	0.1105
C3	0.0
C4	0.03238
C5	1.0
C6	460.11
C7	0.0
C8	422.74
C9	1.0

Comments and conditions

n_α; room temperature.

Conditions

direction: alpha

References

K. Kato, K. Miyata, L. Isaenko, S. Lobanov, V. Vedenyapin, V. Petrov. Phase-matching properties of LiGaS₂ in the 1.025–10.5910 μm spectral range. Opt. Lett., 42, 4363–4366 (2017)

doi:10.1364/ol.42.004363 Phase-matching properties of LiGaS_2 in the 1025–105910 μm spectral range, Optics Letters (2017)

Cite

Kiyoshi Kato et al.. Phase-matching properties of LiGaS_2 in the 1025–105910 μm spectral range. Optics Letters, 42, 4363 (2017), doi:10.1364/ol.42.004363; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 400 wavelengths, the same grid as the API and the library

CSV comma separated TXT tab separated YAML n, k Full database record original YAML All quantities CSV JSON metadata

LiGaS2 (Lithium gallium sulfide, LGS), Kato et al. 2017: n(α) 1.025–10.591 µm: n and k versus wavelength
λ (µm)	n
1.025	2.102441
1.03102	2.102124
1.03707	2.10181
1.04316	2.1015
1.04928	2.101193
1.05544	2.100891
1.06163	2.100591
1.06787	2.100295
1.07414	2.100003
1.08044	2.099713
1.08678	2.099427
1.09316	2.099145
1.09958	2.098865
1.10603	2.098589
1.11253	2.098316
1.11906	2.098046
1.12563	2.097779
1.13223	2.097515
1.13888	2.097254
1.14556	2.096996
1.15229	2.096741
1.15905	2.096489
1.16586	2.09624
1.1727	2.095993
1.17958	2.095749
1.18651	2.095508
1.19347	2.095269
1.20048	2.095033
1.20753	2.0948
1.21461	2.094569
1.22174	2.094341
1.22892	2.094115
1.23613	2.093892
1.24339	2.093671
1.25069	2.093453
1.25803	2.093237
1.26541	2.093023
1.27284	2.092811
1.28031	2.092602
1.28783	2.092395
1.29539	2.09219
1.30299	2.091988
1.31064	2.091787
1.31833	2.091589
1.32607	2.091392
1.33386	2.091198
1.34169	2.091006
1.34956	2.090816
1.35748	2.090627
1.36545	2.090441
1.37347	2.090256
1.38153	2.090074
1.38964	2.089893
1.3978	2.089714
1.406	2.089537
1.41425	2.089362
1.42256	2.089188
1.43091	2.089016
1.43931	2.088846
1.44776	2.088678
1.45625	2.088511
1.4648	2.088345
1.4734	2.088182
1.48205	2.08802
1.49075	2.087859
1.4995	2.0877
1.5083	2.087543
1.51716	2.087387
1.52606	2.087232
1.53502	2.087079
1.54403	2.086927
1.55309	2.086777
1.56221	2.086628
1.57138	2.086481
1.58061	2.086334
1.58988	2.086189
1.59922	2.086046
1.6086	2.085903
1.61805	2.085762
1.62754	2.085622
1.6371	2.085483
1.64671	2.085346
1.65637	2.085209
1.6661	2.085074
1.67588	2.08494
1.68572	2.084807
1.69561	2.084675
1.70556	2.084544
1.71558	2.084414
1.72565	2.084285
1.73578	2.084157
1.74597	2.08403
1.75621	2.083905
1.76652	2.08378
1.77689	2.083656
1.78732	2.083533
1.79782	2.08341
1.80837	2.083289
1.81898	2.083169
1.82966	2.083049
1.8404	2.08293
1.8512	2.082812
1.86207	2.082695
1.873	2.082579
1.884	2.082463
1.89506	2.082348
1.90618	2.082234
1.91737	2.082121
1.92862	2.082008
1.93995	2.081896
1.95133	2.081785
1.96279	2.081674
1.97431	2.081564
1.9859	2.081454
1.99756	2.081345
2.00928	2.081237
2.02108	2.081129
2.03294	2.081022
2.04487	2.080915
2.05688	2.080809
2.06895	2.080704
2.0811	2.080599
2.09331	2.080494
2.1056	2.08039
2.11796	2.080286
2.13039	2.080183
2.1429	2.08008
2.15548	2.079977
2.16813	2.079875
2.18086	2.079774
2.19366	2.079672
2.20654	2.079571
2.21949	2.079471
2.23252	2.07937
2.24562	2.07927
2.2588	2.07917
2.27206	2.079071
2.2854	2.078972
2.29882	2.078873
2.31231	2.078774
2.32588	2.078675
2.33954	2.078577
2.35327	2.078479
2.36708	2.078381
2.38098	2.078283
2.39496	2.078185
2.40901	2.078088
2.42316	2.07799
2.43738	2.077893
2.45169	2.077796
2.46608	2.077699
2.48056	2.077601
2.49512	2.077504
2.50976	2.077407
2.5245	2.07731
2.53931	2.077213
2.55422	2.077116
2.56921	2.077019
2.58429	2.076922
2.59946	2.076825
2.61472	2.076728
2.63007	2.076631
2.64551	2.076533
2.66104	2.076436
2.67666	2.076338
2.69237	2.07624
2.70818	2.076142
2.72408	2.076044
2.74007	2.075946
2.75615	2.075848
2.77233	2.075749
2.7886	2.07565
2.80497	2.075551
2.82144	2.075452
2.838	2.075352
2.85466	2.075252
2.87142	2.075152
2.88827	2.075051
2.90523	2.07495
2.92228	2.074849
2.93943	2.074748
2.95669	2.074646
2.97404	2.074543
2.9915	2.074441
3.00906	2.074338
3.02673	2.074234
3.04449	2.07413
3.06236	2.074025
3.08034	2.07392
3.09842	2.073815
3.11661	2.073709
3.1349	2.073602
3.15331	2.073495
3.17182	2.073388
3.19044	2.073279
3.20916	2.073171
3.228	2.073061
3.24695	2.072951
3.26601	2.07284
3.28518	2.072729
3.30447	2.072617
3.32386	2.072504
3.34338	2.072391
3.363	2.072277
3.38274	2.072162
3.4026	2.072046
3.42257	2.071929
3.44266	2.071812
3.46287	2.071694
3.4832	2.071575
3.50365	2.071455
3.52421	2.071334
3.5449	2.071213
3.56571	2.07109
3.58664	2.070967
3.60769	2.070842
3.62887	2.070717
3.65017	2.07059
3.6716	2.070463
3.69315	2.070334
3.71483	2.070205
3.73664	2.070074
3.75857	2.069942
3.78064	2.06981
3.80283	2.069676
3.82515	2.06954
3.8476	2.069404
3.87019	2.069266
3.89291	2.069128
3.91576	2.068988
3.93875	2.068846
3.96187	2.068703
3.98512	2.068559
4.00852	2.068414
4.03205	2.068267
4.05571	2.068119
4.07952	2.06797
4.10347	2.067819
4.12756	2.067666
4.15179	2.067512
4.17616	2.067357
4.20067	2.0672
4.22533	2.067041
4.25013	2.066881
4.27508	2.066719
4.30018	2.066555
4.32542	2.06639
4.35081	2.066223
4.37635	2.066054
4.40204	2.065883
4.42788	2.065711
4.45387	2.065537
4.48002	2.065361
4.50631	2.065183
4.53277	2.065003
4.55937	2.064821
4.58614	2.064637
4.61306	2.064451
4.64014	2.064263
4.66738	2.064073
4.69477	2.06388
4.72233	2.063686
4.75005	2.063489
4.77794	2.06329
4.80598	2.063089
4.83419	2.062886
4.86257	2.06268
4.89111	2.062471
4.91983	2.062261
4.94871	2.062047
4.97775	2.061832
5.00697	2.061613
5.03637	2.061392
5.06593	2.061169
5.09567	2.060943
5.12558	2.060714
5.15567	2.060482
5.18593	2.060247
5.21637	2.06001
5.24699	2.059769
5.27779	2.059526
5.30877	2.059279
5.33994	2.05903
5.37128	2.058777
5.40281	2.058522
5.43453	2.058263
5.46643	2.058
5.49852	2.057735
5.53079	2.057466
5.56326	2.057194
5.59592	2.056918
5.62877	2.056638
5.66181	2.056355
5.69504	2.056068
5.72847	2.055778
5.7621	2.055484
5.79592	2.055186
5.82994	2.054884
5.86417	2.054578
5.89859	2.054268
5.93322	2.053953
5.96804	2.053635
6.00308	2.053312
6.03832	2.052985
6.07376	2.052654
6.10941	2.052318
6.14528	2.051978
6.18135	2.051632
6.21763	2.051283
6.25413	2.050928
6.29084	2.050568
6.32777	2.050204
6.36492	2.049834
6.40228	2.04946
6.43986	2.04908
6.47766	2.048695
6.51569	2.048304
6.55394	2.047908
6.59241	2.047506
6.63111	2.047098
6.67003	2.046685
6.70918	2.046266
6.74857	2.045841
6.78818	2.045409
6.82803	2.044972
6.86811	2.044528
6.90843	2.044077
6.94898	2.04362
6.98977	2.043156
7.0308	2.042686
7.07207	2.042208
7.11359	2.041724
7.15534	2.041232
7.19735	2.040733
7.2396	2.040226
7.28209	2.039711
7.32484	2.039189
7.36784	2.038659
7.41109	2.038121
7.45459	2.037575
7.49835	2.03702
7.54236	2.036457
7.58664	2.035885
7.63117	2.035304
7.67597	2.034714
7.72103	2.034115
7.76635	2.033506
7.81194	2.032888
7.8578	2.03226
7.90392	2.031622
7.95032	2.030974
7.99699	2.030315
8.04393	2.029646
8.09115	2.028966
8.13864	2.028274
8.18642	2.027572
8.23447	2.026858
8.28281	2.026132
8.33143	2.025394
8.38034	2.024644
8.42953	2.023882
8.47901	2.023106
8.52878	2.022318
8.57885	2.021516
8.62921	2.0207
8.67986	2.019871
8.73081	2.019027
8.78206	2.018169
8.83361	2.017296
8.88547	2.016407
8.93763	2.015503
8.99009	2.014583
9.04286	2.013647
9.09595	2.012694
9.14934	2.011724
9.20305	2.010736
9.25707	2.009731
9.31141	2.008707
9.36607	2.007664
9.42105	2.006603
9.47635	2.005521
9.53198	2.00442
9.58793	2.003297
9.64421	2.002154
9.70082	2.000989
9.75777	1.999802
9.81505	1.998591
9.87266	1.997358
9.93062	1.9961
9.98891	1.994818
10.0475	1.993511
10.1065	1.992177
10.1659	1.990818
10.2255	1.98943
10.2856	1.988015
10.3459	1.986571
10.4067	1.985097
10.4677	1.983593
10.5292	1.982057
10.591	1.980489

Optical transmission calculator

Free-standing sample in vacuum, normal incidence

Transmittance T: —
Reflectance R: —

Fresnel reflection calculator

R_p: —
R_s: —
R = (R_p+R_s)/2: —
Phase φ_p: —
Phase φ_s: —
Brewster angle θ_B: —
Critical angle θ_C: —

LiGaS₂ (Lithium gallium sulfide, LGS): all datasets

About LiGaS2 (Lithium gallium sulfide, LGS)

Lithium gallium sulfide (LiGaS₂, abbreviated as LGS) is a nonlinear optical crystal material often employed in frequency conversion applications, including second harmonic generation and optical parametric oscillation. Its broad transparency range in the infrared spectrum and high nonlinearity make it suitable for laser systems and other photonics applications. Like other nonlinear optical materials, LGS needs to be phase-matched for effective frequency conversion, and its optical properties can vary with temperature and orientation. Special care must be taken in handling and storing the crystal to prevent degradation of its optical qualities.

More about LiGaS2 (Lithium gallium sulfide, LGS) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/LiGaS2/nk/Kato-alpha.yml
ID: ds_c456e2ea920b
API: /v1/datasets/ds_c456e2ea920b

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