Optical glass

1. An optical glass comprising, in expression of atomic %: Ge+Ga; 6% to 30%; S+Se+Te; 50% to 85%; and Ti; 0.001% to 0.5%,

wherein a wavelength (λ T10% ) at a long-wavelength side end which infrared transmittance through a glass plate converted to a thickness of 1 mm based on the optical glass becomes 10% is 12 μm or more.

2. The optical glass according to claim 1 , substantially not comprising As.

3. The optical glass according to claim 1 , comprising, in expression of atomic %:

Ge+Ga; 7% to 25%;

Sb; 0% to 35%;

Bi; 0% to 20%;

Zn; 0% to 20%;

Sn; 0% to 20%;

Si; 0% to 20%;

La; 0% to 20%;

S+Se+Te; 55% to 80%;

Ti; 0.005% to 0.3%;

Li+Na+K+Cs; 0% to 20%; and

F+Cl+Br+I; 0% to 20%, wherein

a glass transition point (Tg) of the optical glass is 140° C. to 550° C.

4. The optical glass according to claim 1 , comprising, in expression of atomic %:

Ge+Ga; 7% to 25%;

Sb; 0% to 35%;

Bi; 0% to 20%;

In; 0% to 20%;

Zn; 0% to 20%;

Sn; 0% to 20%;

Si; 0% to 20%;

La; 0% to 20%;

Y; 0% to 10%;

Gd; 0% to 10%;

Ca; 0% to 20%;

Sr; 0% to 20%;

Ba; 0% to 20%;

S+Se+Te; 55% to 80%;

Ti; 0.005% to 0.3%;

Li+Na+K+Cs; 0% to 20%; and

F+Cl+Br+I; 0% to 20%, wherein

a glass transition point (Tg) of the optical glass is 140° C. to 550° C.

5. The optical glass according to claim 1 , substantially not comprising Se.

6. The optical glass according to claim 1 , comprising, in expression of atomic %:

Ge+Ga; 8% to 23%;

Sb; 2% to 32%;

Bi; 0% to 10%;

In; 0% to 10%;

Zn; 0% to 15%;

Sn; 0% to 15%;

Si; 0% to 15%;

La; 0% to 15%;

Y; 0% to 8%;

Gd; 0% to 8%;

Ca; 0% to 15%;

Sr; 0% to 15%;

Ba; 0% to 15%;

S; 55% to 75%;

Te; 0% to 20%;

S+Te; 55% to 75%;

Ti; 0.01% to 0.2%;

Li+Na+K+Cs; 0% to 10%; and

F+Cl+Br+I; 0% to 10%, and comprising

C; 0.001% to 0.2%.

7. An optical device using the optical glass according to claim 1 .

8. An infrared sensor having the optical device according to claim 7 .