Let \( a_1, \frac{a_2}{2}, \frac{a_3}{2^2}, \ldots, \frac{a_{10}}{2^9} \) be a G.P. of common ratio \( \frac{1}{\sqrt{2}} \). If \( a_1+a_2+\cdots +a_{10}=62 \), then \( a_1 \) is equal to:
\( \sqrt{2}-1 \)
\( 2(2-\sqrt{2})\)
\( 2-\sqrt{2} \)
\( 2(\sqrt{2}-1) \)