求助请问各位大佬我该如何把纵坐标变成指数形式

x1 = [lbk]0, 5, 10, 12, 15, 18, 20[rbk];y1 = [lbk]0.47,0.3978,0.04437, 0.016,0.001526, 0.000037,0[rbk];x2 = x1;y2 = [lbk]0.4957, 0.313, 0.00452, 0.0004745, 0,0, 0[rbk];
figure;hold on;plot(x1, y1, 'DisplayName', '16QAM');plot(x2, y2, 'DisplayName', 'QPSK');title('BER vs. OSNR');xlabel('OSNR (dB)');ylabel('BER');legend('Location', 'best');grid on;