wavelengths
 

GTI mirrors

The higher the GDD, the smaller the spectral bandwidth GTI mirrors are basically Bragg mirrors with ad­ded and precisely adjusted spacer layers in the upper section of the film stack which work like a Gires-Tournois-Interferometer (GTI).

Resonances introduced by the spacer layers can produce very high GDD values but these are limited: The higher the GDD, the smaller the spectral bandwidth (see curves of three different GTI mirrors on the right).

LASEROPTIK offers GTI mirrors with GDD values up to about 5000 fs². Even higher values are possible but will lead to increased optical losses and lower LIDT.

GTI mirrors may be equipped with additional features like a pass band for the pump laser or a tailored transmittance, so they can be used as out-coupling mirrors. A typical application is the dispersion management in Ytterbium based lasers.

Examples

If not mentioned otherwise, all values and diagrams are given

... for the standard substrate material used in the described wavelength area (mostly Fused Silica or CaF2).

... without consideration of the rear surface.

... with EBE coating technique for a good cost-performance ratio.

Customized coatings are available for all types.

 

–––– dashed lines show the zoomed curve with the stated magnification

HR 490–540 nm / 8° s GDD –100 fs² on Si
[B-15915-03]HR 490–540 nm / 8° s GDD –100 fs² on Si

490–540 nm: Rs > 99.9%; GD(Rs) ±2 fs vs. design + const. (IBS-coating)

HR 515 nm / 5° s GDD –350 fs²
[B-18991]HR 515 nm / 5° s GDD –350 fs²

502–522 nm: Rs > 99.8%; GD(Rs) ±3 fs vs. design + const. (IBS-coating)

With the high accuracy of the IBS coating technique, we produce GTI mirrors which are optimized for the GDD but also compensate for the dispersion of other optics within the beam path. GDD targets can be set precisely for every material and specific thickness. The shown coating is optimized for a 3.5 mm thick Ti:Sapphire within the path:

HR 750–850 nm / 5° p GDD –3.5 mm Ti:Sa
[B-19912]HR 750–850 nm / 5° p GDD –3.5 mm Ti:Sa

750-850 nm: Rp > 99.9%; GD(Rp) ±4 fs vs. design + const. (IBS-coating)

HR 1010–1060 nm / 0–10° GDD –500 fs²
[B-12654]HR 1010–1060 nm / 0–10° GDD –500 fs²

1010–1060 nm: R > 99.9%, GDD ±150 fs² (IBS-coating)

HT 980 nm T 2.6% 1055 nm / 0° GDD –600 fs²
[B-11395]HT 980 nm T 2.6% 1055 nm / 0° GDD –600 fs²

980 nm: T > 95%; 1055 nm ±8 nm: R ±0.25%, GDD ±60 fs² (IBS-coating)

HR 1010–1050 nm / 6° p GDD –1000 fs² 
[B-19100]HR 1010–1050 nm / 6° p GDD –1000 fs² 

1010–1050 nm: Rp > 99.9%; GD(Rp) ±8 fs vs. design + const. (IBS-coating)

HT 976 nm T 5% 1030 nm / 0° GDD –1300 fs² 
[B-12655]HT 976 nm T 5% 1030 nm / 0° GDD –1300 fs² 

976 nm: T > 95%; 1030 nm: T ±1%, GDD ±250 fs² (IBS-coating)

HR 1030 nm / 0–5° GDD –2900 fs²
[B-08609]HR 1030 nm / 0–5° GDD –2900 fs²

1030 nm: R > 99.95%, GDD (R) ±500 fs² (IBS-coating)

HR 1290–1650 nm / 0° GDD –100 fs²
[B-18544]HR 1290–1650 nm / 0° GDD –100 fs²

1290–1650 nm: R > 99.9% (goal R > 99.95%); 1305–1640 nm: GDD(R) ±45 fs² (IBS-coating)

HR 1960–2180 nm / 5° p GDD –1000 fs²
[B-17311]HR 1960–2180 nm / 5° p GDD –1000 fs²

1820–2130 nm: Rp > 99.9%; 1820–2200 nm: R > 99.8%; 1960–2180 nm: GDD(Rp) ±350 fs² (IBS-coating)

HR 580–1000 nm / 5° s+p GDD +75 fs²
[B-18459]HR 580–1000 nm / 5° s+p GDD +75 fs²

580–1000 nm: Rs,p > 99%; GD(Rs,p) ±5 fs vs. design + const. (IBS-coating)

HR 1900–2100 nm / 0° GDD +100 fs²
[B-12656]HR 1900–2100 nm / 0° GDD +100 fs²

1900–2100 nm: R > 99.9%, GDD ±15 fs² (IBS-coating)

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