Optical constants

Refractive index of BaGa₄Se₇ (Barium gallium selenide, BGSe)

Kato et al 2017: n(α) 0.901–10.6 µm

Data: formula 4
Range: 0.901–10.59 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: 2.43672
Extinction coefficient k: 0

Permittivity ε₁: 5.93759
Permittivity ε₂: 0

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

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.00509667 µm⁻¹

Group index n_g: 2.45247
Group velocity dispersion: 163.516 fs²/mm

Dispersion parameter D: -32.2584 ps/(nm·km)
Photon energy: 0.401243 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

# BaGa4Se7 (Barium gallium selenide, BGSe): Kato et al 2017: n(α) 0.901–10.6 µm
baga4se7 = ls.fetch_refractiveindex("main", "BaGa4Se7", "Kato-α", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(baga4se7.range_nm)  # (901, 10591) nm
eps = baga4se7.eps([3090])  # 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_076a68d28777/lightsmith"
baga4se7 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(baga4se7.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (baga4se7/kato-2017).

# ... load baga4se7 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=baga4se7)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=901, stop_nm=1000, 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} = 6.72431 + \frac{0.26375 λ^{0.0}}{λ^{2} - {0.04248}^{1.0}} + \frac{602.97 λ^{0.0}}{λ^{2} - {749.87}^{1.0}}

Valid from 0.901 to 10.591 µm.

Coefficients as stored

C_i	Value
C1	6.72431
C2	0.26375
C3	0.0
C4	0.04248
C5	1.0
C6	602.97
C7	0.0
C8	749.87
C9	1.0

Comments and conditions

n_α; room temperature.

Conditions

direction: alpha

References

K. Kato, K. Miyata, V. Petrov. Phase-matching properties of BaGa₄Se₇ for SHG and SFG in the 0.901–10.5910 μm range. Appl. Opt., 56, 2978–2981 (2017)

doi:10.1364/ao.56.002978 Phase-matching properties of BaGa_4Se_7 for SHG and SFG in the 0901–105910 μm range, Applied Optics (2017)

Cite

Kiyoshi Kato, Kentaro Miyata and Valentin Petrov. Phase-matching properties of BaGa_4Se_7 for SHG and SFG in the 0901–105910 μm range. Applied Optics, 56, 2978 (2017), doi:10.1364/ao.56.002978; 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

BaGa4Se7 (Barium gallium selenide, BGSe), Kato et al 2017: n(α) 0.901–10.6 µm: n and k versus wavelength
λ (µm)	n
0.901	2.502434
0.906582	2.501545
0.912198	2.500667
0.91785	2.499801
0.923536	2.498947
0.929257	2.498104
0.935014	2.497272
0.940807	2.496451
0.946635	2.49564
0.9525	2.49484
0.958401	2.494051
0.964338	2.493272
0.970312	2.492503
0.976324	2.491744
0.982372	2.490996
0.988458	2.490256
0.994582	2.489527
1.00074	2.488807
1.00694	2.488096
1.01318	2.487395
1.01946	2.486702
1.02577	2.486019
1.03213	2.485344
1.03852	2.484678
1.04496	2.484021
1.05143	2.483372
1.05794	2.482731
1.0645	2.482099
1.07109	2.481475
1.07773	2.480859
1.08441	2.480251
1.09112	2.47965
1.09788	2.479057
1.10469	2.478472
1.11153	2.477895
1.11842	2.477324
1.12534	2.476761
1.13232	2.476205
1.13933	2.475657
1.14639	2.475115
1.15349	2.47458
1.16064	2.474052
1.16783	2.473531
1.17506	2.473016
1.18234	2.472507
1.18967	2.472006
1.19704	2.47151
1.20445	2.471021
1.21191	2.470538
1.21942	2.470061
1.22698	2.46959
1.23458	2.469125
1.24223	2.468666
1.24992	2.468212
1.25767	2.467764
1.26546	2.467322
1.2733	2.466886
1.28119	2.466454
1.28912	2.466029
1.29711	2.465608
1.30515	2.465193
1.31323	2.464783
1.32137	2.464378
1.32955	2.463978
1.33779	2.463583
1.34608	2.463193
1.35442	2.462808
1.36281	2.462428
1.37125	2.462052
1.37975	2.461681
1.38829	2.461314
1.39689	2.460952
1.40555	2.460595
1.41426	2.460242
1.42302	2.459893
1.43183	2.459548
1.4407	2.459208
1.44963	2.458872
1.45861	2.45854
1.46765	2.458212
1.47674	2.457888
1.48589	2.457568
1.49509	2.457252
1.50436	2.456939
1.51367	2.456631
1.52305	2.456326
1.53249	2.456025
1.54198	2.455727
1.55153	2.455433
1.56115	2.455143
1.57082	2.454856
1.58055	2.454573
1.59034	2.454293
1.60019	2.454016
1.61011	2.453743
1.62008	2.453473
1.63012	2.453206
1.64022	2.452942
1.65038	2.452682
1.6606	2.452424
1.67089	2.45217
1.68124	2.451918
1.69166	2.45167
1.70214	2.451424
1.71268	2.451181
1.72329	2.450942
1.73397	2.450705
1.74471	2.45047
1.75552	2.450239
1.7664	2.45001
1.77734	2.449784
1.78835	2.44956
1.79943	2.449339
1.81058	2.449121
1.8218	2.448905
1.83308	2.448691
1.84444	2.44848
1.85587	2.448272
1.86736	2.448065
1.87893	2.447861
1.89057	2.44766
1.90228	2.44746
1.91407	2.447263
1.92593	2.447069
1.93786	2.446876
1.94986	2.446685
1.96194	2.446497
1.9741	2.44631
1.98633	2.446126
1.99863	2.445944
2.01102	2.445764
2.02347	2.445585
2.03601	2.445409
2.04862	2.445235
2.06132	2.445062
2.07409	2.444891
2.08693	2.444722
2.09986	2.444555
2.11287	2.44439
2.12596	2.444227
2.13913	2.444065
2.15239	2.443905
2.16572	2.443746
2.17914	2.44359
2.19264	2.443434
2.20622	2.443281
2.21989	2.443129
2.23364	2.442978
2.24748	2.44283
2.2614	2.442682
2.27541	2.442536
2.28951	2.442392
2.30369	2.442249
2.31797	2.442107
2.33233	2.441967
2.34677	2.441828
2.36131	2.441691
2.37594	2.441554
2.39066	2.441419
2.40547	2.441286
2.42037	2.441154
2.43537	2.441022
2.45046	2.440893
2.46564	2.440764
2.48091	2.440636
2.49628	2.44051
2.51175	2.440385
2.52731	2.440261
2.54297	2.440138
2.55872	2.440016
2.57457	2.439895
2.59052	2.439775
2.60657	2.439656
2.62272	2.439538
2.63897	2.439422
2.65532	2.439306
2.67177	2.439191
2.68832	2.439077
2.70497	2.438964
2.72173	2.438852
2.73859	2.43874
2.75556	2.43863
2.77263	2.43852
2.78981	2.438412
2.80709	2.438304
2.82448	2.438196
2.84198	2.43809
2.85958	2.437984
2.8773	2.43788
2.89513	2.437775
2.91306	2.437672
2.93111	2.437569
2.94927	2.437467
2.96754	2.437366
2.98592	2.437265
3.00442	2.437165
3.02303	2.437065
3.04176	2.436966
3.06061	2.436868
3.07957	2.43677
3.09865	2.436672
3.11784	2.436576
3.13716	2.436479
3.15659	2.436384
3.17615	2.436288
3.19583	2.436194
3.21563	2.436099
3.23555	2.436005
3.25559	2.435912
3.27576	2.435819
3.29605	2.435726
3.31647	2.435634
3.33702	2.435542
3.35769	2.435451
3.3785	2.435359
3.39943	2.435268
3.42049	2.435178
3.44168	2.435088
3.463	2.434998
3.48445	2.434908
3.50604	2.434818
3.52776	2.434729
3.54961	2.43464
3.57161	2.434551
3.59373	2.434463
3.616	2.434374
3.6384	2.434286
3.66094	2.434198
3.68362	2.43411
3.70644	2.434022
3.7294	2.433934
3.75251	2.433847
3.77575	2.433759
3.79914	2.433671
3.82268	2.433584
3.84636	2.433497
3.87019	2.433409
3.89417	2.433322
3.91829	2.433234
3.94257	2.433147
3.96699	2.43306
3.99157	2.432972
4.0163	2.432885
4.04118	2.432797
4.06622	2.432709
4.09141	2.432621
4.11675	2.432533
4.14226	2.432445
4.16792	2.432357
4.19374	2.432269
4.21972	2.43218
4.24586	2.432091
4.27217	2.432002
4.29863	2.431913
4.32527	2.431824
4.35206	2.431734
4.37902	2.431644
4.40615	2.431554
4.43345	2.431463
4.46091	2.431373
4.48855	2.431281
4.51636	2.43119
4.54434	2.431098
4.57249	2.431006
4.60082	2.430913
4.62932	2.43082
4.658	2.430726
4.68686	2.430633
4.71589	2.430538
4.74511	2.430443
4.77451	2.430348
4.80409	2.430252
4.83385	2.430156
4.86379	2.430059
4.89393	2.429961
4.92425	2.429863
4.95475	2.429765
4.98545	2.429666
5.01633	2.429566
5.04741	2.429465
5.07868	2.429364
5.11014	2.429262
5.1418	2.42916
5.17366	2.429056
5.20571	2.428952
5.23796	2.428848
5.27041	2.428742
5.30306	2.428636
5.33591	2.428529
5.36897	2.428421
5.40223	2.428312
5.4357	2.428202
5.46938	2.428092
5.50326	2.42798
5.53735	2.427868
5.57166	2.427755
5.60618	2.42764
5.64091	2.427525
5.67585	2.427409
5.71102	2.427291
5.7464	2.427173
5.782	2.427053
5.81782	2.426933
5.85386	2.426811
5.89013	2.426688
5.92662	2.426564
5.96333	2.426439
6.00028	2.426312
6.03745	2.426184
6.07485	2.426055
6.11249	2.425925
6.15036	2.425793
6.18846	2.42566
6.2268	2.425526
6.26537	2.42539
6.30419	2.425253
6.34324	2.425114
6.38254	2.424974
6.42208	2.424832
6.46187	2.424689
6.5019	2.424544
6.54218	2.424398
6.58271	2.42425
6.62349	2.4241
6.66453	2.423949
6.70581	2.423796
6.74736	2.423641
6.78916	2.423484
6.83122	2.423326
6.87354	2.423165
6.91612	2.423003
6.95897	2.422839
7.00208	2.422672
7.04546	2.422504
7.08911	2.422334
7.13303	2.422162
7.17722	2.421987
7.22168	2.421811
7.26642	2.421632
7.31144	2.421451
7.35673	2.421268
7.40231	2.421082
7.44817	2.420894
7.49431	2.420704
7.54074	2.420511
7.58746	2.420316
7.63446	2.420118
7.68176	2.419918
7.72935	2.419715
7.77723	2.419509
7.82542	2.419301
7.8739	2.419089
7.92268	2.418875
7.97176	2.418659
8.02114	2.418439
8.07084	2.418216
8.12084	2.41799
8.17115	2.417761
8.22177	2.417529
8.2727	2.417294
8.32396	2.417055
8.37552	2.416813
8.42741	2.416568
8.47962	2.416319
8.53215	2.416067
8.58501	2.415811
8.6382	2.415552
8.69171	2.415289
8.74556	2.415022
8.79974	2.414751
8.85426	2.414476
8.90911	2.414197
8.9643	2.413914
9.01984	2.413627
9.07572	2.413336
9.13195	2.41304
9.18852	2.41274
9.24544	2.412436
9.30272	2.412126
9.36035	2.411813
9.41834	2.411494
9.47669	2.411171
9.5354	2.410842
9.59447	2.410509
9.65391	2.41017
9.71372	2.409826
9.7739	2.409477
9.83445	2.409122
9.89538	2.408762
9.95668	2.408396
10.0184	2.408025
10.0804	2.407647
10.1429	2.407263
10.2057	2.406873
10.2689	2.406477
10.3326	2.406074
10.3966	2.405665
10.461	2.405249
10.5258	2.404827
10.591	2.404397

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: —

BaGa₄Se₇ (Barium gallium selenide, BGSe): all datasets

About BaGa4Se7 (Barium gallium selenide, BGSe)

BaGa₄Se₇, commonly abbreviated as BGSe, is a chalcogenide-based nonlinear optical crystal known for its phase-matching capabilities and broad transparency window. This material is particularly suited for frequency conversion applications in the mid-infrared region, including second-harmonic generation (SHG), sum-frequency generation (SFG), and optical parametric oscillation (OPO). BGSe exhibits high nonlinear optical coefficients, as well as a high laser damage threshold, making it well-suited for high-power applications. The crystal is generally grown using techniques like the Bridgman-Stockbarger method, and can be cut and polished into high-quality facets for optimal performance. One important consideration for this material is its sensitivity to moisture and other environmental factors; thus, careful handling and storage are required to maintain its optical properties. Overall, BGSe offers a compelling combination of properties that make it a valuable material for nonlinear optics, especially for applications requiring high efficiency and broad tunability in the mid-infrared range.

BaGa<sub>4</sub>Se<sub>7</sub> - DienTech

More about BaGa4Se7 (Barium gallium selenide, BGSe) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/BaGa4Se7/nk/Kato-alpha.yml
ID: ds_076a68d28777
API: /v1/datasets/ds_076a68d28777

Plot