HOLLOW-CORE FIBER BASED BROADBAND RADIATION GENERATOR WITH EXTENDED FIBER LIFETIME

1 . An optical component for a broadband radiation source device, the optical component configured to generate broadband radiation upon receiving pump radiation and comprising:

a hollow-core photonic crystal fiber (HC-PCF); and

a gas mixture filling the HC-PCF, wherein the gas mixture comprises a mixture of at least one first gas configured for the generation of the broadband radiation and at least one second gas configured for thermal conditioning of the gas mixture and/or dampening of acoustic waves within the gas mixture, wherein the at least one second gas comprises or consists of helium.

2 . The optical component according to claim 1 , wherein the at least one first gas comprises or consists of one or more selected from: krypton, xenon, argon, neon.

3 . The optical component according to claim 1 , wherein the at least one second gas further comprises one or more molecular gases.

4 . The optical component according to claim 3 , wherein the one or more molecular gases are selected from: nitrogen (N 2 ), oxygen (O 2 ), H 2 O.

5 . The optical component according to claim 1 , wherein the at least one second gas constitutes at least 10% of the gas mixture in mole fraction.

6 . The optical component according to claim 1 , wherein the at least one first gas consists of xenon and the at least one second gas consists of helium, the at least one second gas constituting a mole fraction of equal to or higher than 50%.

7 . The optical component according to claim 6 , wherein the at least one second gas consists of helium constituting 80% or more of the gas mixture in mole fraction.

8 . The optical component according to claim 1 , wherein the at least one first gas consists of krypton and the at least one second gas consists of helium, the at least one second gas constituting a mole fraction of equal to or higher than 20%.

9 . The optical component according to claim 1 , wherein the at least one first gas consists of krypton and the at least one second gas consists of helium, constituting respectively 50%±10% and 50%±10% of the gas mixture in mole fractions.

10 . The optical component according to claim 9 , wherein the at least one first gas consists of argon and the at least one second gas consists of helium, the at least one second gas constituting a mole fraction of equal to or higher than 10%.

11 . The optical component according to claim 10 , wherein the at least one first gas consists of argon constituting 70% or less of the gas mixture in mole fraction and the at least one second gas consists of helium, the at least one second gas constituting 30% or more of the gas mixture in mole fraction.

12 . The optical component according to claim 10 , wherein the at least one first gas consists of argon constituting 90% or less of the gas mixture in mole fraction and the at least one second gas consists of helium, the at least one second gas constituting 10% or more of the gas mixture in mole fraction.

13 . A broadband radiation source device comprising:

the optical component of claim 1 ; and

a pump radiation source configured to generate the pump radiation.

14 . A metrology device comprising the broadband radiation source device according to claim 13 .

15 . A method for configuring an optical component for a source arrangement configured for generating a broadband radiation output, the method comprising:

selecting a hollow-core photonic crystal fiber (HC-PCF) and a gas mixture filling the HC-PCF comprising a first gas for generating the broadband radiation and a second gas comprising helium; and

determining an optimized mole fraction of helium to be present within the gas mixture, wherein the optimized mole fraction of helium is based on one or more selected from:

improving thermal conductivity of the gas mixture;

improving thermal diffusivity of the gas mixture; or

selecting of a desired heat transfer mechanism.

16 . An optical component for a broadband radiation source device configured for generating a broadband output upon receiving pump radiation, the optical component comprising:

a hollow-core photonic crystal fiber (HC-PCF) ; and

a gas mixture filling the HC-PCF,

wherein the gas mixture comprises a mixture of at least one first gas configured for the generation of broadband radiation and at least one second gas configured to improve thermal conductivity of the gas mixture and/or provide acoustic damping of shock waves initiated during the generation of broadband radiation, and

wherein the at least one second gas comprises an atomic gas and the at least one first gas comprises or consists of an atomic gas having a greater atomic weight than the atomic gas within the at least one second gas.

17 . The optical component according to claim 16 , wherein the at least one first gas consists of xenon and the at least one second gas consists of helium, the at least one second gas constituting a mole fraction of equal to or higher than 50%.

18 . The optical component according to claim 16 , wherein the at least one first gas consists of krypton and the at least one second gas consists of helium, the at least one second gas constituting a mole fraction of equal to or higher than 20%.

19 . The optical component according to claim 16 , wherein the at least one first gas consists of krypton and the at least one second gas consists of helium, constituting respectively 50%±10% and 50%÷10% of the gas mixture in mole fractions.

20 . The optical component according to claim 16 , wherein the at least one first gas consists of argon and the at least one second gas consists of helium, the at least one second gas constituting a mole fraction of equal to or higher than 10%.